BoosteD01

Cylinders 1 and 5 are misfiring. Also Idle is a little iffy. Any thoughts??

2000audia6

Is your trouble light on? Have you done any recent maintenance?

Could be spark plugs, ignition coils, or ignition control units (modules).

Buy or borrow a Automotive Diagnostic Code Scanner. There are many different makes and models and names for these. It doesn't need to be expensive or fancy. It just needs the ability to read and erase codes. There is a plug in under your dash. Follow the directions for the scanner.

I have found errors in my 2000 Audi A6 2.7T even when the check engine light (MIL, etc) was not on or would not stay on. The error codes will help point you in the right direction.

One thing that will help your trouble shooting is swapping your Ignition Control Units. Your car will have two of them. They are located under the trim on top of your engine filter housing. There are two bolts holding the units to the filter housing. There are two wire harnesses connecting to each of the ignition control units held in place by metal clips. Once you have the Diagnostic scanner, let it tell you which cylinders are misfiring. Then clear the codes. Then switch the units. (I marked the original configuration with a paint pen before switching units to ensure I didn't change anything but the position of the units.) Then start the engine up and give it a little gas and read the new codes. If the cylinders numbers that misfire change, then the problem is in one of the ignition control units.

quickaudi:STFA

replaced your spark plugs lately?

BoosteD01

yes, all spark plugs have been removed and replaced with new..Aslo No MIL Light..just a sketchy idle.. I did run the VAG and it did see a misfire occur on those two cylinders..

Next step??

faheemo

I've also got the misfire problem on idle.
VAGCom says its cylinder 1 and 3 mainly and a few on cylinder 2.
I've done new plugs and tried swapping the ignition modules around, but no luck as yet.

Any ideas why it's only on one bank of cylinders ?

quickaudi:STFA

O2 sensor going out could cause misfires on one bank, as could a failing EGT sensor

quickaudi:STFA

possibilities: coolant temp sensor, boost leak, EGT sensors, O2 sensors, coil packs, ICMs, fuel injectors, intake leak

start checking!

faheemo

Thanks For the Help,

I've replaced the O2 sensors and spark plugs, ruled out the ICM's and coil packs.
Will check for boost leaks and the rest.

quickaudi:STFA

okay, how did you rule them out?

faheemo

I swapped the Ignition control modules over with each other the misfire didnt move banks.
Also swapped coil packs and miss didnt follow coilpacks.