This is what i've found out. On my car, the stuttering is related to rpms. You guys already know that. but i've also found that the stuttering eases at 3500-4200 range. this is where we have the most torque. Something else i've found is right when i start my car up, the car idles perfect, no stuttering. when i push on the peddle a little bit, up to around 2500, and leave it there, the idles will fluctuate about 500 rpms without me moving my foot. they will just go up and down until i let off or push it in farther. The hesitation usually occurs when the car is under a heavy load, and instead of giving that growl noise when accelerating, it just bucks, hicups and hesitates. If i go up a steep hill it will always hesitate, unless i can downshift and get it into that max tq rpm range. if its over or below that range it misses. I have extreme power loss when like this. You guys probably know that point in the peddle, the last little bit that when your in 5th gear, trying to pull a hill, the last bit of the peddle makes no visible difference. I can floor it and the rpms will slowly go up. and then i can 3/4 throttle it and they will go up at the same speed. but the only difference is that when i'm WOT there is hesitation, at 3/4 there isn't. So i'm thinking airflow also plays another part. I'm going to check all my battery connections, test my copmression, get new plug wires and see what i find. If anyone else expieriences these same symptoms let me know what you think. This is a mild/serious problem with us 420a 2g's, and am wondering if it has something to do with the ecu. anyone running a howell ecu got these problems?

YOu just described my problem to a T. I was/am wondering what the hell is going on. This just recently started and i am planning on replacing my coil pack and my first 02 sensor to see if that does the trick. I assume that this is an 02 sensor problem but feel free to correct me if i am wrong. I am also getting bad gas mileage now which is also giving me this suspicion. I am getting this weird engine code (U3FFF) that noone seems to know what it means. Please enlighten me if you can........

I just purchased some Accel plug wires off of nopi so i'll hope to have them by next week. I'll tell you if it goes away. thats what i've heard anyway. It went away when i changed plugs. Try checking your plugs for oil and your compression. tell me what you get.

NEw Plugs, NEw wires, NEw VC Gasket and NEw Spark plug seals/gaskets. There is no oil in my plugs. I am certain ti is either the coil pack or the 02 sensor.

i swear putting a screw in that egr wire solved this problem .. i'll take a picture of what im taking about later

Well i do have a code p401 for EGR failure. Please share with me what you are talking about. I was going to fix this soon.

Is this just under load? I was just getting tready to post a question about this. I noticed today that when warm and at idle, she sputters once in a while. I know my clutch is on the way out, so I haven't been too worried about it bucking a little now and then under acceleration, but today I kinda lugged it in 3rd and it sounded like ass! AUGH! Otherwise the car runs great. Maybe even better lately (come to think of it).
I've noticed some soot forming on my rear end too lately. If an O2 dies on you, I think the ECU runs a default fuel curve, richening the mix for safety, and maybe making the car feel quicker?
I've got a new O2 as of about 3 mos ago, but I need to do the fuel filter and maybe plug wires. Just wanted to share some symptoms and maybe help out...
Thanks.

Well i will piece it out and see. I will start with the coil pack and Fuel Filter and EGR System and go from there. all this needs to be replaced anyway so it is no biggie. If anyone elses finds anything else out, please let me know as i hate this problem.

same exact prob. was gonna replace coil pack, but wheel bearing came first, now no $$$. i'm also experiancing a lot of oil loss, back of HG, you know that spot, right below the TB on the #4 cylender. so i'm guessing i'm also having compression probs.

wish someone can find a definite answer to this, it's pissing me off. this summer, hopefully soon, new coilpack, wires (plugs get replaced every november, so they are pretty new). and later, HG!!! (oh what fun that's gonna be)

Same exact problem with me, except I have the hesitation at the 4000 rpm range. What's weird though is if when I hit this area, I take my foot off of the gas a little, the car will see the boost and go. But if I just floor it I'll sit at 4000 rpm's until I let off the gas. So I'm guessing airflow too because I changed my plugs, wires, and coil pack. The first time I changed all of these the problem went away, but it came back and when I changed them again to see if that was the problem, it didn't go away this time. Oh, and if it's the o2 sensor, wouldn't we get a cel? This does seem to be a huge problem for us. Someone figure it out!!!

well my car stutters and misfires when I go WOT and it's between 3-4k rpm. After 4k it just boosts fine. So I would get the infamous CEL 43. I would disconnect the battery and reconnect it. Well for first 5-10 minutes black smoke would just come pouring out of the exhaust and the engine would idle very rough. After 10 minutes engine idles fine and runs fine. So my conclusin was, I flooded the engine with too much gas and me running 94 all the time just help with the rich mixture even more. So make sure you guys are running effecient amount of fuel and not more or less.

Am I the only guy with this problem who is NOT turbo?
I replaced the O2 sensor a while back. I have no CEL regarding it, but it seems my most common symptom is rough idle. It stutters every couple of seconds once it's warmed up. Last night she bogged down in 3rd on me. :(
My mileage was still a decent 29.8 mpg as recent as my last tank of gas. I'll have to check it again here this weekend. Anybody find anything out? I really don't want to buy new wires just to have the problem recurr. Thanks. :)

no i have it too. i had my engine fully rebuilt with some serious headwork and cams, oversized valves and a bunch of other stuff. i have an S-Safc. just have to get it installed to see what my mixture is.

i have a problem with is studdering at idle ranger and 2000 when going up a hill. My car is a non turbo 2.0 automatic. it throws a p1390 manufacturer ignition/ misfire code.

i know I'm resurrecting this one from the grave.... BUT. did anyone ever pinpoint an exact cause? lol

Originally posted by corey69
i know I'm resurrecting this one from the grave.... BUT. did anyone ever pinpoint an exact cause? lol

Right, I've had this sort of problem since I've owned the eagle. Just doesn't seem as bad as everyones. Coil, Plugs, Wires.... Need todo O2 sensors.

But doesn't anyone have some new input?

thanks

I've noticed that the problem seems to diminish considerably when I do a fuel system flush, but changing injectors doesn't make it go away

I replaced mine thinking it was that before I replaced the wires (oh well) so if someone wants one this is the deal -- you pay for shipping (whats that 7 bucks??) and you have to pass it along to everyone else once you determine whether or not it is the problem. This way no one goes out and buys a new coil pack without the actual need.

If anyone wants to do this email me at hydnguyen@yahoo.com or IM me at Kahnfucious.

later.

Ive got the same problem too. I get the stuttering when my car is under load in high gears at low rpms. If I go WOT though it basically goes away, but once it did it and it felt like I hit fuel cut, but I know that cant be it. Oh and my car is also backfiring out of the intake. I havent changed my plugs in a while like I used to so Im going to do that, and change the fuel filter since it hasnt been changed for 80,000 miles

i replaced the upstream O2 on my 99 GS with Bosch pt no 13399 (4cyl dodge avenger, since 13425 doesn't fit a 99 :S), and it's still running like crap. guess i'll mess with coil pack / plug wires next... this suxxxx. any suggestions? since my issues started, i've done fuel filter, pvc, plugs. this really suxxx. i wish i knew what suddenly went awry with my car... :(

Custom CAI w/ extra large filter, Front strut tower brace, Rear sway bar, Brembo xDrilled & slotted rotors, Performance Friction pads, Greddy 4:1 header, Greddy SP cat back exhaust, Bridgestone Potenza RE950’s, VIS carbon fiber Hood & pins, Optima Red Top battery, Custom taillights and rear end mod

fuel filter #1 culprit, plugs wires and then fuel pump, coil pack is easily tested too

I've been misfire/backfire/stuttering for almost a year now. Every hill I go, every turn i make... it happens everytime when I floor it. It runs great if I step on the gas soft (1/2 WOT). plugs/wires/coil pack did solve my problem and so as others on here. But, mine came back! so, check them stuff out first!

If not ignition(wires,spark plugs,coil pack) or fuel related(injectors,pump,fuel filter,reg).
1.Might be loose or blocked vac line
2.Might also be crap/deposits in throttle body or small blockage in metal EGR tube.
3.coolant temp sensor might be faulty-ecu might not catch a bad one(check/clean the connections first)
Just my 2 cents (LOL it might be 1 cent)

i don't know what it's called, but that canister thing behind the pass side headlight is ticking loudly, could that cause anything like this? or is the ticking normal?

oh yeah, i'm NOT turbo.

Guys ive been having this problem for over a year now. Im also a 95, which seems to be the year with the most problems. Heres a list of parts replaced in order to remedy this situation...(its long)
gas tank
fuel pump
fuel filter
head gasket
reworked head
plugs
wires
coil
o2 sensor
intake temp sensor
coolant temp sensor
timing belt(thought timing was off)
all seals on motor
New cone intake
battery
cleaned tb/intake manny
muffler
cleared cat
blocked egr tubes
there is probably more but i just cant think of anything more right now. Im seriously tired of the misfiring and i hope someone can come up with a solution. Now whats the deal with the screw through the egr wire??? what did this do and can i see some pictures?
Right now i have a CEL for my front o2, which is fairly new and my ecu says im running very lean. Im leaning towards a new ecu, but i'll replace the o2 sensor first before spending mad money on an ecu. Keep us informed

The metallic cannister is part of the EVAP system. Right around there you got your purge and vent solenoids. I'm thinking one of them might be ticking as opposed to the actuall cannister. I replaced all that stuff a while ago trying to fix the CEl 31, which I've basically narrowed down to the roll over valve on the gas tank.

I've still got my ORIGINAL fuel filter, another guy's got 80K since his last change, anyone actually CHANGE theirs in the last, oh, maybe year and still have this problem? :wary I'm keeping my fingers crossed for a cheap and easy fix.

My coolant is pudding due to a leaky head gasket, but she never EVER runs hot. What's the one thing we all have in common, maint-wise, that we haven't done? Do we all have a dirty, old fuel filters? :P

Sorry man ^ but I had changed my fuel filter about 6 mos before my problem developed. What finally cured my problem was a set of MSD ignition wires.

*****ANYONE OUT THERE KNOW WHO TO REPLACE THE COIL?*****
I'VE BEEN HAVING THE SAME PROBLEM FOR ABOUT 8 MONTHS NOW. I TALKED TO THE PARTS GUY AT THE MITSUBISHI DEALERSHIP AND HE SAID IT COULD EITHER BE THE PLUGS, WIRES, OR COIL....IS THERE ANYONE OUT THERE WHO CAN TELL ME HOW TO REPLACE THE COIL?.....REPLY BACK IF YOU DO....SICK OF THIS CRAP. I KNOW MY CAR CAN RUN FASTER BUT THIS DAMN MISFIRING.


SONNY C.
95 EAGLE TALON ESi
Short Ram Air Intake
APC Intimidator Air Filter
Custom Hi-Flow Straight Pipe Catalytic Converter
Apex'i Megaphone Series Cat-Back Exhaust System

Mitsu I beleive changed my filter little while ago, within a year, and I have hesitiation/chugging like the power stops for one rev a few times at anything below 3k rpms in 2nd gear and up. I dont get any backfiring though. Just hesitation, which Ive noticed is pulling my ignition timing and slowing the car down.

WRITE BACK IF YOU KNOW HOW TO REPLACE THE COIL

Hey Type 3! No need to shout. ;)
It's easy. Buy new coil (Howell has em, etc). Disconnect your plug wires at the coil pack. Unscrew 4 long bolts at the corners of the pack. Unplugg the pack. Lift it off. To reinstall, reverse.
If you aren't sure what the coil IS, then just scroll up this thread and look at the sig pic with the red valve cover. It's the little box with the spark plug wires coming off it.
Looks like I'm going to get the Chilton's out and Ohm out my plug wires to see if they're up to spec. Plugs are cheap and easy, and I'm thinking I might just pop for that Howell coil. Hope that fixes it... :rolleyes

The strange thing is, that it's not backfiring all the time. Only when there are load or etc. My car idles great, and if i slowly accelerate runs good too!
I don't think it's fuel related because it they were bad, shouldn't they be bad throughout the whole time?

*DON'T GO TO THE DEALER!!!(atleast in TN) They said that plug wires were gonna cost me $70 and if I put them on, there is no warrenty on them. So, the only way to get warrenty is let them do it...which will take 30~60min and costs me $40...DAMN!!!
*DONT'T GO TO THE DEALER!!!!(atleast in TN)part 2 I went and asked them if they could take a look at my car and fix the backfire problem.
The first thing they said was that they can take a look and work on it-which costs me a lot of money- BUT they can't guarantee that it will be fixed. Second thing they asked me was if I did any mods to my car. So, I told them that I got a muffler and an intake... they said that is it!! My car was doing all this way before I've installed both of them... So if you are RICH(unlike me) then you should take it to the dealer and pay them a lot of money for BULL SHIT! #*(@$(#&$*()&$()&!@()#*&!()@&<---sorry, that's my anger
:P

I wonder, there are so many of us with the same problem...can we complain to Mitsubishi for possible a recall or something? OR it takes more than just 200cars?(i don't know the exact number but...)

i had my filter changed around 2 years ago, i've only put about 30k on the car.

about the coil, is the msd one that is on modern performances website any good, or should i go with a stock one? or howells?

I haven't changed my fuel filter... Havn't had my car too long but i'm assuming that it needs it. I just checked my compression. i got 200,185,190,195
pretty good. My plug wires should come soon. As far as my IAC goes, what do you guys think it is? the motor or the wiring/ecu? I'm going to price an IAC unless u guys know how much they are.

Might be a good idea to check your fuel pressure. A clogged filter isn't the only cause for reduced fuel pressure, the pump and regulator could be to blame. If your motor is getting the fuel it needs, giving the spark it needs, then suspect something on the control end. PCM, Cam sensor, Crank sensor, etc... I would probably check the cam sensor, though. Take it off, clean it, and RTV it back into place. The gasket for it isn't so hot, if ya know what I mean...
-=B-=

Hey Bill,
That's the guy up in the front right corner right? Driver's side, next to the intake tube? I'll check mine out.

anyone come up with anything for the egr? how do i know if i still have it on my car? i'm almost positive i do. where do the block off plates go?

If you've got that UFO looking thing on the front right corner of your engine, you've more than likely still have EGR. I could be wrong tho, but I'm pretty sure.

My car just started doing this same thing today. As soon as the car reaches 0 vac, it hesitates and sometimes backfires out the intake. I know it is due to fuel being cut because I can see it on my a/f gauge immediately. Every time my car hits 0 vac, my a/f gauge shows waaay lean and acts like it is in open loop mode. I think that the reason for this with my car is because I richened up the 8 injector setup and set it to start squirting fuel at about 1 psi. My guess is that after a few days of driving this way and WOT pulls, the ecu developed a new WOT fuel map for open loop driving. I'm thinking that for some reason, that regardless of the throttle position, the car is going into open loop mode, and the fuel map for it is extremely leaned out due to all the extra fuel that I am adding with the 034EIC at low boost. I am gonna try a few different settings on the EIC and datalog the car tomorrow to try to solve this problem.

For the guy above that was saying that he was getting backfires out the intake, that is a very strong indicator of running too lean. I am almost positive that your problem is that you dont have enough fuel at the point where your car is hesitating. I highly doubt the problem is ignition related.

If its not nessasarily the IAC motor that is causing the problem with the idle, then what is it? I had the multimeter on the sensor wires and it would spike every once in a while from 0 to 12v maybe that is what causes the hesitation... and as far as the motor itself, It moved, but not correctly. I turned my motor on and it came out but when i shut it off a little later(the air was geting through the iac hole and causing high revs) the probe didn't go back in very far at all. like a 1/8th inch. i also had cel 14 one time. hasn't came back...i have 12,15,25,14,25. thats the most cels i've ever gotten. 12 is battery, 15 is speed sensor(my speedo don't work) and both the iac problems and the map cel which is no longer there after clearing the codes.

maybe we should all do the keydance thing and see if we have a common code? I'll be posting what I've got CEL wise in a couple hours...

just did the keydance... nothing new.
The usual suspects:
12
31 (odd this one's there twice now...) x(
31
55

yeah, i have two 25's... sounds like you have a vacuum problem too. it says aan evaporative problem... i have an iac /vacuum problem too.. conection?

Well, I'm not sure why I get the 31 twice. That code has haunted me for almost 2 years now. I like to think my CEL adds about, oh 5hp. :P
In trying to fix the 31 code I have replaced the EVAP Purge solenoid and EVAP Vent solenoid (that's what Satan said it was). I still need to check all the vac lines in and around that area (behind the pass. side bumper light).
I had a technician hook the system up to a "smoke machine" once and they pressurized the EVAP system to see where it was leaking, and the smoke was coming from somewhere on top of the gas tank. Pump etc is okay, but you can't get to the rollover valve without dropping the tank, so I think that's it since it would be the most trouble.
I'm gonna try to get the fuel filter changed out this weekend and see if that doesn't help. Has anybody else made any progress? Did we ever see where that screw in the EGR wire went? If we all get this figured out and taken care of, it will have to be the biggest group fix in the history of 2GNT! :thumbsup

yeah, will someone post a couple pics of the egr system. and anything having to do with the "screw" that needs tightened or whatever... i read this somewhere on these boards:

From what i understand, the ECU will perform a EGR test, normally at cold engine conditions. The ECU will partially close off the IAC valve, and open up the EGR valve. If the EGR is working, the exra air flow from the EGR will compensate for the closed off IAC valve, and all is good. If the EGR is not working properly, or has been blocked off, then the motor will stumble a bit, then trip the CEL for insufficient EGR flow. The ECU will always try and activate the EGR solenoid, hooked up or not. If the actual soleniod has been disconnected, then you will get a CEL for that. If the EGR pipe has been blocked off, then you will eventually get a insuf flow code for that. The EGR is mainly used at cold startup, to help warm the motor faster, and also lower emmisions, and its also used seldomly at part throttle, and WOT to help lower emmissions.

This is odd, because my car runs good right at startup. no hesitations. then a little bit later, it starts to stumble. so maybe there is an IAC/EGR relation here. anyone else's car idle ok right at startup or when your car is cold?

Seems to me like mine idles fine when cold. It's once it gets warm that the idles kinda sputter intermittently (about every 4 seconds).
I changed my original FUEL FILTER this afternoon. It had almost 140K on it. :P Car runs a lot smoother now, but I still get that damn puttering when it's warmed up.

I tested the COIL PACK at the plug and all 4 terminals. Chilton's says you should get 11.5 - 13.5 (in that area) KOhms across your terminals. (from one point to the one directly across from it) I got 12.5. Spec? Check.

I tested my PLUG WIRES. Chilton says they should run about 8KOhm. Here's where I got some variance. 1 & 4 came in at 4KOhm and 2 & 3 pulled 3KOhm. I would think lower resistance is better in this area, but I don't know at this point. I would guess excess resitance would lead to misfiring due to a weaker spark. Most aftermarket have a lower resistance if I'm right, so this doesn't matter muc, I think.

I also noticed oil all over my PCV hose from the valve cover. Pulled the PCV check it for movement only, not vac, and put it back in. I'm going to go back through this thread and see if there's any thing else on the simple side I can check out one night this week. Let's get this fixed! }(

*EDIT*
I was reading the forums at The Ranger Station (trying to fix a crappy idle on my bro's Ranger) and saw someone mention that if you have too much oil on your K&N or similar filter, it can be sucked into the TB and make you idle funny. I didn't feel like pulling all that off to check sine I'll be P&P that thing here pretty soon, but do we all have K&N or oiled filters here?

Where's that "badest mother fucker on the planet" Dino with the low down on what this is, huh? hehe :7

hmm. I'll check my plug wires and see if i get the same results. but i'm getting new wires in the next couple days so i'll check them also and see if they are good before even using them. and as far as an oiled filter, i'm using the stock one. but i've cut off the little dirt/dust catcher from the bottom of the intake so i could fit some air horns there. i don't think it is the cause for it. My car ran GREAT today. atleast it wasn't sputtering so much. i also had the problem where you can't seem to get past 3k rpms in 5th. i put my silencer on so i can't really hear the sputtering so much. I am leaning towards a couple things. I think that either 1) the egr is stuck/dirty/broken or the IAC is one of those. or there is sumthin ignition related. I just don't see how replacing the plugs or plug wires will make it temporarily go away. ecu related? sensors. there is just too much stuff to check. I'm going to hit up the egr/iac part. because i have cell 25 anyway.(iac) can anyone get a pic of the egr and the valve that needs cleaned?

Yeah my car is bone stock and it happens so I dont think its mod related, although it may be different studdering/hesitation/chugging whatever it can be explained as. Soon Im going to replace the valve cover gaskets, change the plugs and wires again, clean the cam position sensor and gasket, change PCV. If this doesnt work Im trying the coil pack. Hopefully Ill get it fixed before that.

well when I checked my spark plugs they were white, which would mean im running lean, I think im going to give changing the fuel filter a shot, cuz I have a little over 80000 miles on my car less than 30000 on the block :) but i dont think the filter has been changed since it was new.

you guys that have lumpy idles and EGR codes. are you all 95's?

if so do you still have the EGR stuff that was connected to the stock air box?

if so that was recalled years ago. mitsu will remove the solenoid and that other little metal peice and bolt the EGR off. than they erase the codes and do something to the computer so the errors don't come back

im a 95 and ive talked to quite a few people with the same problem and they are 95 as well

no, can't be that, I have a 97 bone stock and it does the same thing. Only started recently though, at 73k miles.

can't just be a 95 thing.
I have a 97 - hacked airbox w/ a K&N drop in = only engine mod (yet)
Gonna hook it up to run4cvr's PocketLogger here this Wedensday and see if he sees anything (also checking for someone else on here who thinks they don't read the 97 ECU).
Planning on pulling the Cam sensor thingy and cleaning it too. Almost there, aren't we!

If only we could set up a multiple option poll where we could check all the things we've tried to see if there was a common link here... :P

well i fixed my problem. i had the same problem with the hesitation and power loss and such. i replaced my coil, wires, plugs, o2, TPS, Idle air solenoid, MAP and still had the prob and then finally took my intake manifold off and turned out i was missing parts of my intake manifold gasket. i replaced that and now i have no more problems with anything.

Ok here's a long shot. Seems like this problem started happening about a year ago, regardless of year, mods, or mileage. So maybe gasoline has been altered nationwide somehow, and is causing problems with our cars. Anyone know if this is possible?

i searched but can't find it.

What is the best replacement for the ignition coil, how much is it, and where do i get it? Couldn't find anything on autozone's site.

EDIT: Oh and I don't need something fancy, regular replacement is fine.

jeff

Guys I have been having the same hesitation problem for over a year and it seems that nothing works. I cant pass 4,000 rpm in any gear except 1st. Sometimes I can pass 4,000 put rpms go up really slow.Also when I press the pedal all the way i feel the car hesitating maybe there is a blocking in the cataylic converter? Tell me what you think. Has anyone changed theres recently? :-(

What was missing from your intake mani gasket? Was it worn thru somewhere? I don't see how a piece of my intake mani gasket could be the culprit since mine's never been off! :o
So, since my fuel filter was obviously in shitty condition to begin with (I can tell a difference once I get out of the stuttering shit), I popped for some 89 octane and a bottle of Chevron Techron injector cleaner. So far, no change. I DID notice when the AC is on it seems to be worse.
This is really starting to piss me the fuck off. x( Driving in the 1Krpm to 3Krpm area just sucks now. I am planning on getting plug wires and maybe a new coilpack here in the next couple weeks. In the meantime, I'm gonna datalog it tomorrow evening and try to check some vac lines out this weekend.
I'm really getting sick of this shit. Sooner or later there will be nothing left to replace, huh? :P

well besides changing the wires, plugs, coil etc the only things that seemed to work for other Dsm owner was: loose wire on front of O2 sensor, disconecting and reconnecting map sensor,ECt sensor, as well as a green and black wired disconnected underneath battery in the main wiring harness. I dont have time to do all these things soon though can anyone else help? Im thinking its my Cat just dont want to spend a fortune, I already spent 4K.

I changed my 02 sensor and it ended all my problems. It was so fried that the end broke off and it melted what was left. After that was installed and ECU was reset eveything returned to normal even on hills.

Right, but a broken o2 sensor would definitely cause a CEL. So obviously that needed replacement. What about the people (including me) who have hesitation but never get CEL's? My car hesitates but I don't have a CEL on.

jeff

Well, my car has gone from bad to worse. The stuttering has taken over the entire PRM range. My car sounds like an old hippie van at idle and is barely driveable. I have to nurse it off the line and can only give it about 20% throttle or else I misfire like a moFo.
The only good news? I got a new CEL doing the key dance. It's a CEL 43. The first thing listed on the CEL list here is primary coil #1 or #2 on the ignition coil. It also says it could be misfire in 1,2,3 or 4, but if you want to read up on it, you can link to the list here
http://www.2gnt.com/nuke/modules.php?name=Sections&op=viewarticle&artid=8
Looks like this 2GNTer is getting a new coilpack. SOON! I'll post back if this doesn't work, as well as anything out of the ordinary from the datalogging tonight (assuming I can run it well enough to get some input) :P

i have cel 42 now. i think it comes up 3 times too.
one of my friends said my car blows black smoke..:(
here are the codes

42 Fuel pump relay control circuit Harness and connector / Fuel pump relay

42 No MFI relay (ASD relay) output voltage at PCM Harness and connector / MFI relay (ASD relay)

42 MFI relay (ASD relay) control circuit Harness and connector / Fuel pump relay

i also get 12 which is battery and 15 which is speed sensor which i already know. and:

25 Idle air control motor circuit Harness and connector / Idle air control motor

25 Target idle not reached (k200 r/min) Harness and connector / Idle air control motor / Vaccuum leak


today, i was driving my car over a hill to school. the WHOLE WAY no warm air came out of my heater. and i check my gague and it was almost maxed out. first thought was no radiator fluid but i turned it off and coasted, little later its at normal again... then it spikes back up to max, and fluctuated a little from then on... messed up! what is wrong with my car??????????

number one you need a thermostat, number two a new iac motor. If any of you wash your engine on a normal basis, check the spark plug wells for liquid. The smallest amount will cause hesitation.

when i get a job and my first paycheck, the first thing i'm getting is a coilpack from howell, the msd one. i hope that fixes mine, but that will be a few weeks. ;( after that, head gasket. while the head is off i'll probably replace the intake manifold gasket and the valve cover gasket, if my car didn't run into the bearing prob i'd probably get some valve springs from howell also.

oh, no CEL's here!

I am now optimistic that I have this problem tracked down (for my situation anyway) :rolleyes
John and Mike hooked me up to the PocketLOGGER an hour ago and found out that I had a missfire in cylinder #2. I switched the plug wires between #2 and #3 and cleared all the codes. Drove the car to school and sat in the parking lot watching the datalogger run. Nothing. I turned on the AC for a load and the car bogged way down, almost died and threw a CEL 43 again. This time PocketLOGGER read misfire in cylinder #3. I doubt a coil pack would get finicky like that on me, but I'm buying some cheap NGK plug wires ASAP and see what happens.
As of about 30 minutes ago, I am officially sold on the PocketLOGGER. :thumbsup

I actually wasn't getting a CEL light on the 02 sensor. IT was something i just decided to try after doing some research on backfire and running rich. If i were yyou guys, I would check your 02 sensors to see if it is ok. There were no indication other then the backfire that something was wrong.

i changed my plugs last night. when i pulled in, it drove like shiat. then, i changed plugs and runs perfect again. woo hoo i have that power back. perfect idle and only cels are 12 and 15. yay! my heater prob i think was i was low on water. i put some in there and i could see my thermostat working so i got it to work now... i ohmed my new plug wires and got like 900 and my old ones, i got like 3000-3500 for the short ones and 4000-4500 for the long ones!!!!! damn. also, my crank case breater tube is broken and barely fitso n the end of the VC now. what do i do about that? and how much is a pocket logger anyhow?

www.pocketlogger.com for info on that one.
and just some FYI on your plug wires, that's what I pulled when I ohmed them out. OEM are supposed to be at about 8000ohm!
until I get the new wires, I continue to run like shit :(

>www.pocketlogger.com for info on that one.
>and just some FYI on your plug wires, that's what I pulled
>when I ohmed them out. OEM are supposed to be at about
>8000ohm!
>until I get the new wires, I continue to run like shit :(

I thought you said you tested the plug wires and they were in spec? Chiltons wrong or you fat fingered your ohm meter :P

8k? that is horrible isn't it? i thought you want the least resistance. and i ment plug WIRES not plugs when i said that above.

I say it again. The Chilton's manual I have says that all 4 plug WIRES should ohm out to 8KOhm. "If they vary, replace them." It doesn't even give a tolerance. :rolleyes
I agree with you guys. Lower resistance is generally preferred in this area, but that's what my Chilton's said. When I mentioned being in spec, I was referring to the coil pack. Across the two rear terminals I was spec, across the two front terminals I was spec and even both tests at the "flat pin" connector were dead on for Chilton's.
HOWEVER---I just got home from AutoZone, where I pulled a redneck parking lot install (new plug wires $40 - Bosch OEM) and the car runs good as new. Hardly even cranks before it turns over.
WHAT I'VE LEARNED HERE---If you haven't changed your plug wires, maybe find a buddy without the problem who'll let you swap out with his for 10 minutes to see if anything changes. If changing the wires helps, well, duh.
IF YOU HAVE NEWER WIRES---maybe try getting some of that grease they offer for your connections. My new wires came greased and a packet of it is only a few cents.
BEST OF LUCK TO EVERYONE STILL FIGHTING WITH THIS BITCH.
:thumbsup

this was a complete PITA for me. i don't know about you guys, but this is great information. so i'm compiling a FAQ that maybe dino will post up or something. dunno when i'll get it dun but i need an email to send it to when it is.

I had a similar issue soon after I got my car. My buddy suggested I check the gapping on my plugs, and they were soo off I don't know how the car was able to maintain idle at any rpm. Regapped them to factory spec and the hesitation problem went away. Just my .02.

i have this damn problem, and i have tried, coil, wires, plugs(gapped at .040), fuel filter, got a test pipe, and replace valve cover gaskets, I have no clue what to do next, should i replace sensors? or the ECU itself? im about to just get rid of the damn thing, someone help me

check ur 02 sensor.... u can unscrew it and look visibly at it.

and what would it look like if it were bad? like crap?

melted off. i dunno. i've actually never done it. ask bigbald, i think his went bad.

One of my friends has a '95 GS with Hahn St.2. He is misfiring terribly about 4.5k or 5k all the way to redline under WOT only. He has put new wires, plugs, O2 sensor, taken cat off, replaced intake man. gasket, fuel filter, new injectors, and fuel injector cleaner. Does anyone know what else it might be? He checked the codes, but it only gave him the pulsed air injection and IAC doesn't have enough voltage. Would the IAC cel have anything to do with it?? Any help is appreciated.

Your friend needs to have the pulsed air system removed because it was a recall, for the 95's, but I doubt that is causing the real issue though.

I'll jump on the bandwagon also.....
I drive a 95 Avenger with the 420a, I have the exact same hesitation problem. Non-turbo, automatic. Here is a list of the work I have done (personally) in the last while, also I have had this problem for upwards of a year.

~just replaced coil today (no output on #3)
~MSD wires are less than 6 months old and check out good (ohms)
~new plugs today also
~new top end gaskets and rebuilt head (timing belt broke)
~changed out injectors today (another used set)
~checked voltages at TPS, good
~checked voltages and heater in the O2 sensor... voltages seemed screwy, all over the place... from 200mv up to 800mv's at idle (normal?)
~going to change fuel filter tommorrow, it needs it anyways
~NO CEL, ever, yes the bulb works (unless i unplug a sensor at idle)
~plugged EGR system, no change
~also changed MAP with another used one, no change

I want to check out the fuel presure during driving, and see what happens, anyone else do this yet? If so what are your findings?

One odd-ball thing I noticed was when I was checking TPS voltages, I was hearing a buzzing sound (continous, never changed), the key was ON and engine was OFF. I traced it to the ECM. The ECM is buzzing... this can't be normal.

I did drive the car with the O2 sensor unplugged, (open loop?), and there was no differance at all! I am going to replace the O2 for $hits and giggles.

My hesitation/misfire problem is the same as all of you have described pretty much. I can get to WOT if I ease into it, but if I get on the pedal fast it bucks and farts, backfires through the intake, huge power loss. The problem doesn't seem to be as bad over 3000 RPM, but the more load the worse it is.

Check your ECM's with the power on and engine off to see if you can hear anything......

I'll be keeping an eye on this thread and I will post of any changes/repairs.

Steve

Let me be the first to say, ive probably had this problem longer than anyone here. 3 years of the exact symptoms your describing here and 3 thousand dollars later ive finally realized that my CLUTCH is to blame. Everything clicked yesterday on my 5.5 hour drive home. The car runs normally under light acceleration and constant speed, but when pushed up a hill or quick throttle response the car will bog down and start to hesitate. Im serious when i say that for three years its just gotten worse and worse for me. Im going to purchase a pt cruiser clutch within a week and replace it within a month. Im dead set on the fact that it has to be my clutch slipping...150,876 miles on an oem clutch must be its limit.

chef: were you getting misfiring problems and motor stutter also? if not you may not having the same problem, just needed to replace a worn clutch or bent fork?

i've had this problem very lightly for awhile, not much power loss or hesitation before, just once every few days under acceleration i'd hear a detonation. just rebuilt the auto tranny and now its pretty bad.. had excessive backfiring in my intake under 3000 rpm, power loss, hesitation, and the strong growl turned into something more of a sore throat.. checked the plugs and cylinder 1 was covered in soot, rest werent quite as bad, switched them with ngk vpowers gapped at ~.042 (i think thats within spec?) and i just checked them (4-5 days later) and all the rings are now covered in soot, guess i'm running rich...
i'm getting error codes 12, 44, 22, 55. 12 and 55 are nothing, 44 is ect voltage, which i just changed to a new one 3 weeks ago, 22 is batt temp sensor(where is that?), battery light is on, but i just got my friends orion yellow top with new gold terminals and voltage is 13-14. so i think i may have a faulty ecu. anyone got an extra they know is good?
radiator has been flushed, about to swap in a used iac motor from a guy on the board (thanks!) and probably gonna swap the t.b. gasket while i'm in there, anything else i should do? changed my air filter couple of days ago too.
wires i tested at : 2060khom, 1400khom, 1500khom, 2020khom which i believe is ok, coil tested at harness connector was in spec
i get no misfire in high rpm range, but under load and going up hills under 3000 gives me severe power loss, backfiring/misfiring and usually can't really get above 40mph on even a moderate hill. has everyone here check their compression also?

1996 eclipse gs non turbo automatic

i forgot to mention, it did drive much better after changing the plugs, but still misfiring and power loss

so today i'm driving to work (after having taken out my plugs and wires for inspection last night- see above post) and it drives fine! didn't misfire once, got some slight stuttering ( a clackety clack noise) at low rpm, but for the most part power was back and smooth.... really strange, maybe wires just needed to be replugged or spark plugs needed to be retightened... i'm gonna wait before i claim success, drive it a bit to make sure its not a fluke

Andrew (my friend) thinks that his clutch is going bad. When he goes 1/2 throttle he can rev all the way to 7, but you can tell that the clutch is slipping on it. Could that be the problem?

When he goes full throttle, about 4.8k or 5k it just starts missing really bad. It sounds like a muffled machine gun firing.

well tranny and motor are essentially completely seperate systems on manual cars... if the clutch is bad, i'd say replace that first before trying to deal w/ the misfiring problem. the only electrical connection i think the manual tranny has is the speed output sensor but i don't think if there were anything wrong with that, that it would cause misfiring.. anyone?

my car STARTED to do this recently again. but its gone now....fukkin weird. im replacin my clutch now anyways. we'll see how it goes. im replacing all my vac lines too.

granted, i didn't read the whole thread but i've had this same hesitation problem. I changed plugs, wires, fuel filter and coil (from 96 style harness to 97 up style harness). but when we were splicing the connection to the new coil we fucked it up. even though it was done on par with a chiltons manual it was wrong. my car was still misfiring and hesistating in the lower ranges and i was getting pissed off about it. long story short, 2 of the wires from the coil harness were in the wrong place, and that was the end of my hesitation problems.

i swapped my 95 coil for the newer version as well, do you have a picture of the wiring now that its working correctly, or can you explain which wires go where?

i have a 97 rs and i have this same crap hapening .if i replace my plugs its is fine but in one day the plugs foul out again and its back to normal stumbling again. the plugs are white like theyve been way too hot. but why? i get code 31 also. ive reaplaced alot and still comes on.so i dissconnected every hose from the EVAP canister and blocked off the vacuum lines to it but still i get this prob. spark plugs fix it but foul out within a day. why is this? i get no other code// i am about to bust out my CAT to see if that could bo clogged and causing this but i am out of ideas. if would have never bought this car if i knew this would happen . only 82K on whole car from dealer. i dunno... help....

Originally posted by EclipsedChef
i swapped my 95 coil for the newer version as well, do you have a picture of the wiring now that its working correctly, or can you explain which wires go where?

I replaced my coil also with a newer model... i'll look into anything at this point.

Back from the dead...

I'm having all the same issues discussed in here, backfiring, no pull at all under 3k RPMs, hesitation. '99 GS. From what I've read and guessed, I think it's my upstream O2 sensor. I'll know by tomorrow afternoon.

I disabled my EGR system and blocked it off. Got rid of my hesitation when hitting 0 vac, or light application of throttle while driving around.

Can you link me to a 'how-to'? Could this possibly hurt anything?

Your car is freaking awesome, btw...

Custom CAI w/ extra large filter, Front strut tower brace, Rear sway bar, Brembo xDrilled & slotted rotors, Performance Friction pads, Greddy 4:1 header, Greddy SP cat back exhaust, Bridgestone Potenza RE950’s, VIS carbon fiber Hood & pins, Optima Red Top battery, Custom taillights and rear end mod

Originally posted by snufalufagus040
Can you link me to a 'how-to'? Could this possibly hurt anything? Your car is freaking awesome, btw... Custom CAI w/ extra large filter, Front strut tower brace, Rear sway bar, Brembo xDrilled & slotted rotors, Performance Friction pads, Greddy 4:1 header, Greddy SP cat back exhaust, Bridgestone Potenza RE950’s, VIS carbon fiber Hood & pins, Optima Red Top battery, Custom taillights and rear end mod

Who me, or the 1 billion posts above me?

Ya you... :)

Custom CAI w/ extra large filter, Front strut tower brace, Rear sway bar, Brembo xDrilled & slotted rotors, Performance Friction pads, Greddy 4:1 header, Greddy SP cat back exhaust, Bridgestone Potenza RE950’s, VIS carbon fiber Hood & pins, Optima Red Top battery, Custom taillights and rear end mod

I'm going to hold of on the EGR bypass because I fixed my issue. I changed my plugs, got 8.5mm wires, and new MSD coil pack. Car runs better than it ever had. Think I had a bad plug wire. I'm so glad I finally fixed this crap!


1999 GS OZ Edition (her name's Janet)

~~Custom CAI w/ extra large filter, Front strut tower brace, Rear sway bar, Brembo xDrilled & slotted rotors, Performance Friction pads, Greddy 4:1 header, Greddy SP cat back exhaust, Bridgestone Potenza RE950’s, VIS carbon fiber Hood & pins, Optima Red Top battery, MSD Blaster Coil and 8.5mm wires, Custom taillights and rear end mod~~

I'm suffering from the same problem. It was gradual at first. I noticed I needed more power when i'm going into first, otherwise the motor boggs down and I get closee to stalling. If i'm in 5th going around 40 and I have to decelerate for whatever reason, I can't get back to 40 without either downshifting or putting the petal to the floor( I'm used to getting at least a little more pull all the way through 5). Plugs, wires, and oil may need to be changed but I found something funny: My dipstick smells like fuel. I'm still diagnosing, but its possible it may be piston rings.

I'm having a little trouble with finding how to pull my error codes ( my check engine light came on after about a week and a half of this power problem ), any one know a good site with code descriptions and how to pull them?

Its a '98 GS i've owned for about a year, but it was down for about 3 months while I replaced 4 valves bent by a snapped timing belt. Haven't really done much research or work beyond that and regular maintenance. Its got 111k miles.

google OBD trouble codes. I refuse to believe you are having trouble finding info on them.

Are you sure nothing else is damaged from the timing belt failure? head integrity, pistons, etc.

If you can replace valves pulling codes is easier than oil change. The port is under the dash, driver's side. Get a scan gauge or similar.

And way to raise an old thread too.

Hmm. I actually found a lot of good information in here. As Im also having the same problem.

My car idles around 900 and will miss every 4 seconds or so like DR1665 said. I also have the intake backfire, hesitation until 3k or so, white plugs, and generally less power.

Coil, plugs, wires were all replaced at the same time about 5k miles before this happened, MSD coil and wires btw. I know for a fact one of my O2 sensors (or both) are bad. Fuel filter has almost 9k on it. Ive also heard the fast ticking by the canister. No codes other than rear o2 sensor yet.

i kinda having the same prob....except my car has almost 171000, miles on it...i replaced the spark plugs, and wires, looks like a newer coil pack..its weird cause the ecu gave me like 6 codes....lol...maybe ill take a trip to the junkyard and just get every sensor that i can grab?

Ok, Im not sure if this is the link between us or not. I noticed a few people having these problems have MSD wires. Today I threw my old, danky stock wires back on to check the resistance in my MSDs. I start my car, bam, misfire is gone. Ive been driving it all day and it hasnt bucked once. I bought these wires "lightly used", so that might have something to do with it, but Ive heard of other people having similar problems...

well, my car started not starting...it still has the 500rpm fluctuation at 2500 rpm and again at 3700 rpm, but now its like i got worse, sometime it wont rev past 400 rpms, i would have to restart it. then it would start then die, and it would start again and slowing climb up to idle (900rpm), while i would have to floor it...ive changed the coil pack, asd relays, spark plugs, wires, and the cam sensor IAC. The only things i havent changed are the fuel filter and the crank angle sensor....so now it wont even start, it would just keep turn over, and over again and again....the ecu did throw a code for the crank sensor, so im going to change that and then see what happens

Try checking the conection at the cam sensor, my car was sputtering like crazy, and it got to the point where my car wouldn't even idle fine. while it was acting up I wiggled the wires at the sensor and the car shut off. I removed the connector and I reconnected it and I pushed the connector in to make sure it was tight, then I started the car and it drove perfect, I'm not saying this will fix every car with this problem. Just letting you guys know something else to check for.

Eagle192, I have recently started having the exact problem. Both of my O2's are new, (Universal and spliced in), coil pack, wires and plugs are new. No codes. It will crank turn over and immediately die. From reading through this entire thread I noticed a common detail of the plugs looking like the car has run lean. Mine are the opposite. They are black and sometimes saturated with fuel depending on how many times I try to crank consecutively. Before it wouldn't start completely I could get it to run, idle fine even rev. I would turn it off and try to restart and have the same no-start situation. I'm just going down the list now. Checking wiring, ranges anything. This has been ongoing for probably the last 4 years now just now it's not driveable. I'll post up what I do find though. Hopefully it relates to our problems.

I have had this problem too for a couple of years now!
I did all the wires coil pack bla bla.

This seems to have happened shortly after I removed my EGR..??

I get a 43

and a 23 I replaced the IAT sensor 23 went away back came back also for me this is a intermittent problem happening at WOT more times then not!!???


WTF

I'm thinking I may have a FCD problem or fuel pump...?

Hey I have 97-GST it would sputter on top end and felt like fuel cut-off ran good at an idle and during normal driving but when I hit high RPM’s it took a dump. After checking everything I changed my plug wires and WOW it solved everything. Now I have a good pull

PLEASE HELP!

I search the forum already with related issues as mine,They only help rule out my problem.

FOR a week now ive been having a misfire or stumble between 2500rpm and up.The misfire will come and go while cruising between those rpms and every time the cel flashes it also flashes when free rev but no misfire. Ive been turbo for 5 years now, i have a FCD, SFMU, and a rebuilt motor with 4,000miles. This is my daily driver And im forced to drive i to work during the week.

The misfire started after i ran my car at the track. I made 3 runs, all three had the misfire. i try to adjust my sfmu after the first run but it didn't help. Also my car died twice in the track parking lot while idling. At the time i figured something came unplugged or fcd need adjust and i would check it when i got home. On my way back the misfire would happen between 2500 and up under a load and every time it misfired the cel would blink.

Its been a week since it started and i ruled out a few things.
FCD TPS MAP Coilpack wires


Keydance 12 32 61 55

Hello
I have a 97 GSt and had the same problem!!
I check boost leak, plugs and just about everything else.
It turned out it was the plug wired although the wires seemed to be working they failed under a load

I replaced the wires with NGK ME77 that I purchased from
Ohe’s Performance Parts
Now it pulls thru all gears and no sputter

Originally posted by paul97
Hello I have a 97 GSt and had the same problem!! I check boost leak, plugs and just about everything else. It turned out it was the plug wired although the wires seemed to be working they failed under a load I replaced the wires with NGK ME77 that I purchased from Ohe’s Performance Parts Now it pulls thru all gears and no sputter

I have aftermarket and stock wires, i changed them out a no difference. The plugs look good. Do you have a 4g63?

yes
send me an e-mail i think i can help you
pohe@socal.rr.com

Originally posted by paul97
yes send me an e-mail i think i can help you pohe@socal.rr.com

Thanks for the help. I scanned my car earlier and got PO403 and PO106. PO 403 is there due to egr block off, and would the PO106 come on because my FCD?

PROBLEM SOLVED!

I have adjustable cam gears, and my exhaust cam gear Adjustments came loose and my exhaust cam was advanced 10 degrees. I put lock tight this time on the adjustment screws and adjusted it back stock.

Fixed my misfire during cruising.

Thanks for the Help guys.

Originally posted by 420AYE
This is what i've found out. On my car, the stuttering is related to rpms. You guys already know that. but i've also found that the stuttering eases at 3500-4200 range. this is where we have the most torque. Something else i've found is right when i start my car up, the car idles perfect, no stuttering. when i push on the peddle a little bit, up to around 2500, and leave it there, the idles will fluctuate about 500 rpms without me moving my foot. they will just go up and down until i let off or push it in farther. The hesitation usually occurs when the car is under a heavy load, and instead of giving that growl noise when accelerating, it just bucks, hicups and hesitates. If i go up a steep hill it will always hesitate, unless i can downshift and get it into that max tq rpm range. if its over or below that range it misses. I have extreme power loss when like this. You guys probably know that point in the peddle, the last little bit that when your in 5th gear, trying to pull a hill, the last bit of the peddle makes no visible difference. I can floor it and the rpms will slowly go up. and then i can 3/4 throttle it and they will go up at the same speed. but the only difference is that when i'm WOT there is hesitation, at 3/4 there isn't. So i'm thinking airflow also plays another part. I'm going to check all my battery connections, test my copmression, get new plug wires and see what i find. If anyone else expieriences these same symptoms let me know what you think. This is a mild/serious problem with us 420a 2g's, and am wondering if it has something to do with the ecu. anyone running a howell ecu got these problems?

Ok my turn. I've read thus entire post. I have a similar issue. 99 Gs mtx. Idle, partial throttles and clutching. Seems there are 4g63, 420a turbos and 420a's in this post. Code for Ses light that I have is bank01 rich. I found that my egr hose was worn and broken. I've replace that and still same symptom but it has helps the idle. I'm leanin towards my tps and or cps. I'll unplug my 02 sensor this evening and pull codes again. By the by my pocketlogger is showing unregistered today so I'll have to go to Autozone to pull the codes quicker. If you have this problem regap your plugs, check the wires for arching and look for broken air hoses. Those should always be 1st on the list for high mileage vehicles.
I'll keep ya posted.

Hi all,
New to forum. Read thru entire post. My prob is a little different.
95gs 420a newly rebuilt stock engine. New plugs, wires, fuel filter, MAP sensor, Crank sensor, vac lines and clutch.
Coil pack checks good. Plugs look good when pulled.
Runs great 1st thru 3rd gear. In 4th and 5th it has a stutter / hesitation. (almost like fuel cut)
Only CEL code from key dance is pulsed air injection that was removed before I bought the car. (clearly didn't reflash ECM grrr)
Tried running injector cleaner through the tank as the car was off the road for 1-1/2 years during rebuilding.
Doesn't seem to be TPS since it runs great until shifting into higher gears. New clutch, so it's not slipping.
Common suggestions like fuel pump and injectors should act bad in all gears, no? (Same with most sensors.)
I'm really stumped.
Any ideas from the 2g guru's?

Originally posted by 95gsrebuild
Hi all, New to forum. Read thru entire post. My prob is a little different. 95gs 420a newly rebuilt stock engine. New plugs, wires, fuel filter, MAP sensor, Crank sensor, vac lines and clutch. Coil pack checks good. Plugs look good when pulled. Runs great 1st thru 3rd gear. In 4th and 5th it has a stutter / hesitation. (almost like fuel cut) Only CEL code from key dance is pulsed air injection that was removed before I bought the car. (clearly didn't reflash ECM grrr) Tried running injector cleaner through the tank as the car was off the road for 1-1/2 years during rebuilding. Doesn't seem to be TPS since it runs great until shifting into higher gears. New clutch, so it's not slipping. Common suggestions like fuel pump and injectors should act bad in all gears, no? (Same with most sensors.) I'm really stumped. Any ideas from the 2g guru's?

misfires and fuel cut are a completely different feeling. So in that your description confuses me. I'd say check for cracking vacuums lines. Troubleshoot this: when you are in 4th and 5th gear does it misfire at WOT? At what rpm range does the symptom show. Test in neutral gradually increase revs until you see/hear misfire and compare tto road test. Come back and let us know.

Ok, the problem does not exist when the engine is not engaged, at any rpm. The problem is not present at any rpm in 1st through third gear. Once you shift into fourth, it does not seem that it is RPM sensitve. Rather when you are accelerating, you feel it lagging / jerking / missing. Feels like fuel cut to me, but it seems engine load related rather than RPM. RPM's do increase when accelerating, but more slowly than it should, due to the interruption in smooth accel. Same in 5th gear.
I replaced all vac lines running to the intake manifold and MAP sensor. (along with new MAP.)
Note also that there is a random stall when cold. Only happens once in a while. When it does happen, it dies very quickly with no miss, backfire or any other symptoms. It just shuts off. Starts back up and idles fine.
The symptoms don't make sense to me.