rough idle during cold start/ multiple misfires - AudiForums.com


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Old 01-14-2010, 04:34 PM
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Default rough idle during cold start/ multiple misfires

i have a 2000 A4 1.8t (ATW). i have recently had issues with my idle surging during cold starts. and if you try to drive while the RPM's are still elevated then it runs horrible and is completely bogged down. but if you let it idle until the RPM's drop down to normal, then it runs fine. i pulled my codes and got a "random/multiple cylinder misfire" and a "cylinder 2 misfire". i cleared the codes and have driven around trying to get them to come back so i can verify that it is cylinder 2 that shows misfire every time, or if it was actually a random misfire and it just happened to be cylinder 2 that time. but i havent gotten the codes to come back yet. my car is chipped and normall boosts to 17psi and holds. but since this started happening, it have noticed that it will overboost. if i go WOT then it will hit 20 or 21 psi and start breaking up from fuel cut. so i am wondering if the problems could be linked. i have had similar problems in the past and it always stopped when i changed my spark plugs, but i changed my plugs last week and it didnt change anything. any suggestions? i am going to try cleaning my MAF and see if that helps, and as soon as i can get the codes to come back, i will try switching the coil packs around to see if the problems follows the coil pack. but anything else i should be looking at in the meantime?
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Old 01-14-2010, 05:19 PM
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coil packs
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Old 01-14-2010, 07:17 PM
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so u think 1 coil pack would cause all these issues?
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Old 01-14-2010, 09:05 PM
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I don't see how a bad coil pack will create higher boost? But I could see how it would run like crap, since its a 4 cyl if 1 cyl was misfiring all the time it would HARDLY run. How bout coolant temp sensor? Sounds silly but its the first thing the car looks at when starting, and considering its temp related...just a thought, how bout idle control valve, possibly not opening? Although I was under the influence that if its bad the car won't even idle when cold. Anyways hope this throws some ideas in your head. Feel free to update.
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Old 01-14-2010, 09:34 PM
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Quote:
Originally Posted by Andrew149 View Post
coil packs
+1

Also check your spark plugs to make sure they are gapped correctly.

I don't know if everyone know this, but the coil packs were recalled so everyone gets the updated ones for free. Call your local dealer and set up an appointment. I got something from Audi USA about it a few months ago.
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Old 01-14-2010, 11:13 PM
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clear the codes, swap the coils around like you said your going to do, drive for a bit, then scan it and see if the misfire is following the coil. are you getting a flashing CEL?
to much psi could be a few things, wastegate, faulty N75, CRIMPED HOSE between the wastegate to boost controller (N75 or mbc), or compressor hosing to boost controller (N75 or mbc), if your using a mbc the settings are to high or the unit is on its way out.
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Old 01-15-2010, 09:11 AM
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I have been driving it pretty hard the last 2 days trying to get the misfire codes to come back but they havent yet. But nothing else has changed. I replaced the plugs last week and gapped them to .028 since i'm chipped. I will swap the coils around as soon as i get the codes to come back and see what happens. I also changed the coolant temp sensor a month or 2 ago so i dont see that going bad again so quickly. I also have a forge 007 divertor valve in place of the N75. but i will look for crimped hoses everywhere and make sure all vacuum lines are connected. i will call audi and see about the recall on coil packs, i hadnt heard anything about that so that would be a nice cheap fix
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Old 01-15-2010, 09:13 AM
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Quote:
Originally Posted by jmgrande View Post
i don't know if everyone know this, but the coil packs were recalled so everyone gets the updated ones for free. Call your local dealer and set up an appointment. I got something from audi usa about it a few months ago.
2001+
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Old 01-15-2010, 09:48 AM
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i called Audi and they said the recall doesnt apply to all B5 A4's. only the people that received notification in the mail from Audi receive the new coil's from the recall and i didnt receive any letters so i guess it doesnt apply to my vin.
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Old 01-15-2010, 11:59 AM
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Quote:
Originally Posted by pete7 View Post
i called Audi and they said the recall doesnt apply to all B5 A4's. only the people that received notification in the mail from Audi receive the new coil's from the recall and i didnt receive any letters so i guess it doesnt apply to my vin.
Sorry about that, I guess dragonrage is right, 2001+
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18t, 2001, a4, audi, coil, cold, idle, misfire, pack, plug, recall, rough, spark, start, tt

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