Happy New Year guys! (It seems I haven't been on to post *but I've been reading* much the past couple of weeks due to a lot of holiday commitments.)

Well, I've come to see if anyone can identify with this problem since I have no idea. I have a noticeable misfire/vibration at idle up to about 2500 rpm's. After that, the car sounds fine. However, at every rpm, the power of the car is significantly lacking. I've already checked and abundance of things, and I still can't get to the bottom of it. I'm suspecting a possible problem with either a faulty injector, possible valvetrain failure (rocker, lifter..etc.), or a skipped belt tooth. I'm actually hoping the problem is related wholly to the engine, since I'm having my spare engine being rebuilt at the machine shop with forged internals, however, it appears at this point (after a good compression check), that isn't the case.

In case the problem is electrically related though, I want to get this figured out.

Here's what I've checked/replaced:

-ignition coil
-spark plugs
-plug wires
-compression good (170's across)
-timing belt intact, but I haven't checked all the marks, save for the cams
-only CEL is EGR related

Anyone have any ideas, please suggest. I'd rather eliminate any easy possibilities before I start doing the difficult. You'd think after 33,000 turbocharged miles, it'd be obviously the ring lands or something, but it isn't. The car still boosts fine as well.

This all started after one time inadvertantly leaving the car in gear and letting off the clutch, giving you that jolt we all know and love. I've done it probably a half dozen times before, but this appears to be the first time with consequences.

what do the color of your plugs look like, that will tell u fuel and tuneing, got any egt guages?

if they are cardboard brown or darker u aren't lean but if they are pitch black u may be running too much fuel and killing the motor maybe post fuel setting and one of the turbo guys can reveiw that cause im not as knowledagble on the pressure setting and such,

i think it could be ignition related?

how did u check plug wires and coil replacethem?

how about vacume leaks?

burning any exxtra oil?

tapping noises?

sounds like some type of ignition or some type of vacume leak,

how long has it been happening did u change the type oof fuel uve been usging latly, do they use oxigenated fuel around your area ? and did they just switch to it for winter time?

sorry about all the questions just trying to help answer and the most info to get to the bottom of it..

I entirely replaced the plugs and plug wires and coil. They look fine.

I think whatever happened may have happened because of the jolt.

The fuel has always treated me well here. I always use 93 octane.

I thought it was ignition related as well, at first. However, having changed all the ignition related components, I think the problem probably lies elsewhere. My oil levels also look good. I don't have an oil pressure guage, but the levels are always high and I frequently check my oil.

Curiously though, my long term fuel trims are really high at about ~24% or so around idle. But my timing is as high as ever, with full boost bringing my timing advance to almost 17-18.

welcome aboard counselor for I am in the same boat. Been happening ever since my cam sensor wires melted and shorted out the whole car. There are times when the engine sounds like it's a bout to blow. Yet I do not know what's causing this problem.

have you checked out your turbo? like the turbine and compressor wheels to make sure they rotate smoothly.

Turbo is unrelated to the problem. It misfires without the turbo activated.

what did you gap your plugs to? i have the same thing, my plugs show a white buildup which means lean. i need to replace my plugs and wires and possibly my coil too. and i need to see if my injecters are plugged or my fuel pump is acting up because every plug shows lean. one has oil on the threads of the plug and the compression is slightly lower 160 i think the rest are 180 or so. maybe i have a hg leak. who knows, besides that damn jolting and like u said, a power lack, my car runs fine.

Plugs are gapped to .034. They look carboned which are just fine. Fueling doesn't appear to be the problem, unless it jsut happened. I'm not driving the talon right now until I figure out the problem.

how about checking all of your rocker arms to be sure none are broken?

id check to see if the timing belt skipped a tooth on one of the cams. A cracked rocker arm/roller or something else in the vavletrain could also do it i guess but i dont see why it would smooth itself out at higher rpms.

When my rockers broke, 2 different times, the car would feel pretty normal from idle to 3500 rpms and then it would just fall on it's ass from 4000 up but that's N/A, with you being turbo you may not notice as much since the air is forced thru the one valve that would be open.

When first reading, I said ignition/wires also but seeing as how you have changed them, I'm not sure, how's the A/F when it happens?

________________________________________________________________________________________
Car Sold


http://hometown.aol.com/ohshootuhh/
www.Fast420A.com

dayam this is tricky b/c usually it's ignition related when the car stumbles in low rpms, but gets better as rpms increase. but since you got that covered... hmmmm. I had the exact same scenario as you were explaining but the cause was a bad spark wire/grounding plug. This may just be a stupid question, but have you checked the fuel filter? that's the only other cause I can think of for stumbling in the lower rpms but resolving in the higher rpms.

What about, O2 sensors? Crank or cam angle sensors?

Do you have any valvetrain noice? Like bad lifters or rockers?

Let me know if you want me to come down and lend a hand sometime.

1997 Eclipse RS (in winter slumber for head gasket repair and other projects)

He who knows men is clever; He who knows himself has insight.
He who conquers men has force; He who conquers himself is truly strong.
-Lao Tzu

Injen CAI, AFX 55mm TB, P&P Intake Manifold, Crower Stage 2 Cams, Hooker Header, GS-T Muffler, AFX UDP, Apexi S-AFC

Usually if it is a sensor problem he would be getting a CEL, and then they tell you the problem.. In this case however, it is tough to tell... I will do some thinking this afternoon and try to give a follow up post.

Thanks for the thoughts guys.

Although in the higher RPM's the car no longer makes the missing noise, it still falls flat on its face throughout all the RPM's. I think I'll pull the valve cover this weekend to see if the rocker arms are good. I partially suspect the timing belt as well, but I would think that would have tripped a code. Additionally, it's not very easy to merely check the marks of the timing, since you have to pull the lower timing belt cover which is a real chore, since it's all in one piece. I can turn the timing belt though with the lower crankshaft bolt and line up the upper marks.

I'll cross my fingers on the problem being a broken lifter. Again, the only code is the EGR. Vacuum lines are fine. I'll give the cam sensor a look tonight.

O2's are fine, and they cycle well. I've even tried disconnecting the EIC, to see if that effects anything, to no avail.

Trust me, it's LITERALLY a 30 minute process to change the rockers and lifters after having broken a few and changed them many times. Just pop off the valve cover, should take 10 minutes to do that and look for the top of a valve without a rocker on it. Hopefully, you don't have this happen, though the first time it happened to me, I drove for 3 weeks before figuring out the problem, the 2nd time, I felt it break and drove home and had the car running again with another stock rocker within 1/2 an hour.




I'll post the how to pics just incase it is one or someone else has the problem.










________________________________________________________________________________________
Car Sold


http://hometown.aol.com/ohshootuhh/
www.Fast420A.com

Am I the only one who doesn't like the idea of digging around my head with a couple screwdrivers?

If you do change out lifters/rockers (with the motor on it's way, unless is demolished... Make sure to pump up the lifters prior to install.

Also, what about injectors? maybe a clogged or stuck injector? What does your O2 reading look like when it's misfiring?

1997 Eclipse RS (in winter slumber for head gasket repair and other projects)

He who knows men is clever; He who knows himself has insight.
He who conquers men has force; He who conquers himself is truly strong.
-Lao Tzu

Injen CAI, AFX 55mm TB, P&P Intake Manifold, Crower Stage 2 Cams, Hooker Header, GS-T Muffler, AFX UDP, Apexi S-AFC

Does your car have a cat still? it may be plugged causing the loss in power...just another thought. Could be fuel related though..or possibly timing.

All of the above are very viable and likely culprits to my problem.

However, my stock cat is gone in favor of a straight through high flow cat. (looks more like a resonator, but it doesnt trigger a CEL)

A clogged or stuck injector is very much something I suspect. However, I've tried to use a stethoscope to try and listen for operational clicking of the injectors without much success. Do you listen to a particular part of the injector to hear it?

Thanks for the post, Kyle. I had read your old post concerning the lifters/rockers repair and have long considered that as a possible source of my talon's woes.

I'll check all of this out this weekend! Thanks guys! I'll keep this string updated.

Jason, check the IAT sensor on the back of the intake manifold. It's very close to the firewall, and I've several 2gnt's with front end damage have the IAT hit the firewall. It's possible the motor rocked hard enough to hit the sensor on the firewall, cracking it. At the least you'd have a small vacuum leak. At worst you'd be getting a bad vacuum leak AND incorrect (read low) intake temps, which would richen up the mixture until the car goes into open loop. Just a thought.

BTW, as long as the sensor still functions (likely), it will not throw a cel if it's dangling in mid air - out of the intake mani.

It looks good, Greg. :-( (thanks for the idea though)

(btw, I do remember that functioning properly from the datalogger and my discussion with Dino.)

Did you pull the EGR out and thats why your pullin the code?

Why not start from there? If you do still have the EGR on your motor and your pulling a code it could be stuck open. This would give you poor low/mid power because your engine is breathing exhaust and is struggling. Once you hit higher RPMs your boosting forcing more air into the motor dilluting the exhaust a bit.

just my 2 cents ;-)

Thanks guys for all of the help last week in trying to figure out what the problem was.

It turned out to be a dead injector in cylinder #3. Go figure.

Big thanks to Dino also, for advising me on the method to cut off(dremel) those metal injector harness clips on the top of the fuel rail for easier access. That made changing out injectors a LOT easier.

Hey counselor how did you find out or check for a faulty injector. Cause my engine sounds like it's misfiring and shakes wildly at idle.

I used the factory service manual primarily. They have a troubleshooting section, that checklists a variety of things, and references other sections on how to check those systems. Ignitionary stuff came first. I've become very familiar with what I need to do to check the coil, wires, and plugs. (using a multimeter)

That led me to the fuel system. Luckily, there's really not much to fuel, asides from the fuel pump and injectors. Since, I always have my fuel pressure gauge setup, I knew my pump was operational.

To check the fuel injectors, the first thing to check is using a mechanic's stethoscope. They only cost like $5, and they're very useful; much more handy than a screwdriver. You take the stethoscope and apply the probe to the body of the fuel injector. You should hear a very distinct and clear clicking noise. If you do, it's operating. If not, it's failed. My #3 injector was quiet as a mouse.

Of note, there are further tests for examing injectors though that include using a multimeter on their terminals, as well as examining the injector connectors.

Thanks again guys. Probably like a lot of you, I had never dreamt that a fuel injector would completely die.