Ok i just got my portfueler on and here is the problem.
i have that stupid idle to on throttle hesitation problem
there are 288 posts that i saw about hesititation and everyone says its either fuel filter, coil, wires, or plugs

it ran fine before the portfueler installation
no problems

when you are under the hood and pull the throttle open you hear the car gulp air while the engine dies and then picks back up

if you hold the throttle at the dying point it still picks back up and the engine revs

i did put a 55mm throttle body on during the install
and there is light showing around the butterfly plate
could that be it???

i am also getting code p0300 multiple cylinder misfire
on my pocketlogger

ok
took it for a drive

dumbass me
i think that the multiple cylinder misfire CEL came from me testing the stutter box on my msd

it seems to have smoothed out very little hesitation now

and when i got back it idles at 950 rpms give or take +/-
100

nothing noticable to the ear with the idle unlesss you are looking at the pocketlogger youd never detect the idle wasnt a smooth note

short term fuel trim is going between -5 and +3
timing is right at 8 at idle
and i cant hear a boost leak anywhere
i should test it with my air tank to make sure

wow
ok just in case someone else does this stupid stupid thing
and takes the check valve out before looking at which way it goes

from the evap canister to the intake there is a one way check valve. air must be able to go from the canister to the intake
i still couldnt get the hesistation completely gone but then i noticed that the hose was sucking shut.
i unhooked the hose and the idle jumped up a little.
when i covered the hose the engine almost shut off befor the IAC could take control.

i put the check valve back in and it seems to be working fine now

hopefully

ok well i thought that was the problem

unless of course something else came along with the same symptons
any i cant find exact matches on any post for what its doing
most hesitation i have seen is during acceleration

mine sitting at idle
fine 800rpms

starts to stumble 200-1500 then smooths out a little
i am guessing that is because of the egr being blocked

worst problem,

when i am slowing down as soon as i push the clutch in the rpms drop to about 1100 which is normal for our cars when coasting so i have read but it sometimes not all the time but sometimes hunt for idle
meaning it revs from 100 to 1500 all the way until you come to a complete stop
as soon as the car stops moving
it goes straight to 800 and stays there until you start moving and then start coasting with the clutch in again.

clutch out no problems
acceleration pulls hard no problems
and even still it doesnt do it all the time.

so far
replaced IAC
replaced MAP
did a boost leak test on the manifold fixed everwhere i heard air hissing.

tps shows constant 11 on my pocketlogger while it is surging
air fuel goes from 12 to 20 on my wideband and then when the idle levels off it goes to 14

both short and long term fuel trims are always +/-5

could the whole thing be egr related


it wasnt doing it before i put on the 3" turbo back btw
it had hesitation but i figured that out
this is new

massive points to anyone that can help

someone
anyone

please

Just as a guess, I'd agree with you regarding the EGR. It closes the IAC and opens the EGR (if I'm not mistaken) to check for airflow and to activate the recirculation, which is probably while the idle freaks out. The computer's expecting air to flow, but there isn't any.

Just a thought. Try hooking up your EGR hardware, but don't bolt it up to the head, only to the intake and see how it idles. When it opens the EGR, it should suck in fresh air and idle fine.

wouldnt it always suck air then because the valve that controls open and closed is near where the egr goes into the head.
the mounting point on the intake is just a hole

interesting note however. last night i noticed that the blue silicon vacuum lines were sucking shut
i replaced the two main ones that were completely shut with regular rubber lines and today instead of an idle surge
while coasting it would idle at 1500 never higher never lower and then settle to 800-900 when a complete stop is reached.

definetly an improvement over the surging
so today i am going to replace every single silicon line with rubber and see what happens

its progress at least

i did get a code 0401 egr failure today though but when i restarted the car it was gone

considering the egr pipe is on my workbench that one i understand

yeah you just found your problem. those colored hoses suck(or dont) i had a similar problem. thought i would dress up the motor alittle. had my waste gate set a 8 psi. put the silicone hose there and everywhere else. went for a spin. drove good for about 5 mins. had a stang mess with me and i let it go. shifted from 1st to second and my bov sounded louder then ever. the car pulled hard to. was at about 6000 rpm in third and no pull. looked at my wideband it was like 15.5 and i was pulling 15 psi. could have blown something up. that hose was toast. don't think i huryt anything but get rid of those things.

already working on it
i went today and bought about 20' of good thick rubber vacuum hose.

hopefully by tomorrow this hassle will all be a memory

still going to put the egr back in

eventually


i also thought what the hell and bought a can of seafoam to try as well
now i just need to find a place that needs fumigation so i can smoke up the place without having the fire dept called

hey i have had my egr blocked for well over a year with no problems.

emissions
they dont test but they actually look here
last year this old fat guy actually tried to crawl under my car to look to see if i still had a cat

Originally posted by baxsom
emissions they dont test but they actually look here last year this old fat guy actually tried to crawl under my car to look to see if i still had a cat

I don't have cats, so I worry whenever I take mine. I went to a place off Marbach & Ellison to get it inspected. They popped the hood, but that's it.

I took my GF's car to a shop off S. Flores & Military and he actuall tested the gas cap.

As far as the EGR thing, yes, it would constantly suck air if the pipe wasn't hooked to anything. The idea was to hook everything up, without actually bolting it up to the head, but you found your problem already.

yeah i think i got the problem solved

the egr is plugged at the intake
and the engine so other than a stumble every now and then when the egr test is done
that seems to be ok

today i replaced every single silicon line with oem quality rubber ones

i am not going to claim victory yet
but now while coasting
idle is a constant 1100 rpms
still idle is 900ish

i will give it another couple of tries before i call it done.

DAMN DAMN DAMN DAMN DAMN

ok i am beginning to think i am going to have to rip the entire intake back off and redo it

what the hell could be the problem

once again

cold start is a pita
it idles fine
almost dies and then catches up
then continues to do that until the car is warm

then driving
drives fine
no problem pulls good

when you let off the gas and press in the clutch
rpms drop quick
until it hits idle and then it revs from 500 to 1500
until you come to a complete stop
once you hit a complete stop
and i mean as soon as the car stops rolling
idle is perfect

basically the same damn problem i have been ranting about this entire thread
i though i had it beat
with the vacuum lines
nope

today just as bad if not worse

could the egr being blocked off have this effect
no one has ever talked about it doing that before

so far
new IAT
new TPS
new MAP
new AIT
new coolant sensor
new vacuum lines

no vacuum leaks that i can find with spraying carb cleaner anywhere

has anyone ever even heard of this problem before

i've been experiencing similar problems (no CEL's tho).I explained them to DarkOne, he said to me it sounds like symptoms of a failing front O2 sensor? Im going to try that. Also, check the o-rings on your injectors?

here's what I replaced with no resolve:

New ECU
MFI & Fuel pump relays
IAC
Crank sensor
Cam sensor
Coolant Temp sensor
MAP Sensor
Fuel Filter
Air Filter
Spark Plugs
Plug wires are pretty new
Coil Pack is fine
PCV Hose (was cracked)
Checked EGR Tube for blockage

probably even more

i am getting a new o2 sensor tonight
fuel pump is good
injectors are new and i cant find any leaks around them

i did notice that the blinky light thing that is occuping a hole in my gauge pillar isnt moving as fast as it used to so hopefully the new sensor will help

Did it work? I replaced my front one, seems to have helped... heres what it looked like (below).Its actually bit darker than the pic shows because of the flash I think. Maybe I need to replace the one behind the CAT too? Im sure its just as bad...

Baxom, I don't think it's your O2 sensor. You said it did it when you were starting up, until it warms up. The ECU doesn't look at the O2 sensor when the car is warming up since it's in open loop mode.

The comment about when you come to a complete stop intrigues me(post date jan 24) When you stopped, it was fine, and then it starts acting up again when you move.

I wonder if it's a VSS-vehicle speed sensor.

I noticed that neither of you replaced that.

Just a thought since I can imagine you're frustrated with this.

Brian

PS. I would check the EGR, since that will have control on the idle as Cougar said before. That would be my first choice. Then you can take my other advice.