well i couldnt find anything obviously wrong. no disconnected or broken vacuum lines. i still havent gotten the fault codes to come back yet so i cant do anything with the coils yet. but its still running rough on cold starts and idle surging for about 30 seconds, so is there anything else that would cause this without throwing a code?

 

Like we said, it's probably the coil packs. How many miles are on your car and have you ever done them?

 

If you have a VAGcom, check your O2 readings at startup. Is your secondary air pump running and functioning correctly?

 

Have you checked the idle control valve? If you have to, remove it and apply 12v power and a ground to make sure it opens and closes. If it does operate correctly that's not the issue, its easy.

 

i have 118,000 miles on my car now. i have replaced 1 coilpack since ive owned the car (2 years) but not the other 3. i thought coilpacks didnt go bad over a period of time, i thought that they just failed and once they do fail that they never work again. not intermitantly like mine seems to be doing cause i cant get the codes to come back. i do have vag-com so i will play with it and see what my O2 readings are at start-up. my secondary air pump is working properly. it will take me a few days to check out the O2 sensors though cause my car is getting painted right now so i wont post again til tuesday

 

well i wasnt sure exactly which block i was supposed to use to check my O2 sensors today with vag-com but this is what i got...these are all start-up readings. in block 30- precat sensor flashed back and forth from 110 to 010 and postcat flashed from 100 to 000. they will hold at 110 @ 100 for a few seconds and then flicker the values 010 @ 000 for about 1/2 a second and then go back to the higher values. in block 31 at start up i got .020 V precat & .435V postcat. after the RPM's drop to normal these values went to the precat varying anywhere from .060 to .710V and the post cat pretty much stayed at .435V. in block 32 i had 0% for both sensors the entire time, no matter whether it was on cold start or not. in block 37 it said "system ok" so i assume that means both sensors are working properly. plus i changed my precat sensor about a year ago. but last night i was driving and the car actually backfired a few times and almost died on cold-start up, but yet i still didnt get any misfire codes so i'm not sure whats going on at all. i think i'm gonna change the coolant temp sensor again, even tho i changed it a couple months ago. thats the only thing i can think of that would make it act this way w/o throwing any codes. if you guys have any other suggestions, let me know.

 

SAP has no effect on how the car runs.

 

yeah i know it doesnt, i went without my SAP for several months before i decided to replace it. but mine is functioning fine tho, to answer tweaked's question.

 

ok, so i replaced my coolant temp sensor again even tho its only a couple months old and that didnt help. i then took our my maf sensor (which isjust over a year old) and cleaned it with MAF cleaner spray and that didnt help. i still cant get the misfire code to come back so i dont want to just spend $200 on all new coil packs and have that not fix anything. i am gonna be listing my car for sale as soon as i fix this issue so i dont want to just throw money at it for good measure. is there anything else that i should be looking at? i mean, on cold starts, it idle jumps all over the place and acts like it almost wants to die, and then idles fine after about 30 seconds. but even after its warmed up, the car still doesnt run like it should. it breaks up under boost and just doesnt feel near as powerful as it should. i know i can do a boost leak check but thats not gonna explain the weird cold start idle issue so i dont think thats the problem. there has to be a sensor somewhere that is causing this, right? any help would be great...

 

Take out your front O2 sensor completely and see if it cold starts easier. Just a temporary test. Car shouldn't need to O2 sensor for cold starts, and if it starts easier, than a clogged catalytic converter (or something else in the exhaust) is your problem or at least part of it.