A6 2.7t Random missfire in needs of advice and help
 

Hey i got a 2004 a6 2.7t and i got random missfire on all cylinders. I been chasing this for over a year now. I just recently in the past month i changed all spark plugs ngk, brand new oem coils, new 02 sensors, and new maf sensor. I have been searching for a possible boost leak or vacuum leak for months but no luck. Any ideas on what to search for or what to teat/try next. Also my engine is a 04 BEL engine so you can rule out the icms. Also my car is chipped stage one so the rear 02s or deleted only the fronts where changed out. I cant seem to find the cars disease for random missfire.

Does anyone have any sugestions???

How do you know its a miss fire on all cylinders? Is there a specific code that its throwing?

From past experience on different engine platforms, usually when all cylinders miss fire its a failing crank sensor.

Don't know if this applies to your model year, but I thought I share it...

https://www.audiworld.com/forums/2-7...p0300-2846545/

Good Luck!

I have random missfire for all cylinders. Also cel always blinking if car is idling long. And has rought idle as well as hesitates once in the blue.

maybe, you need to replace ICM. In my case that works after change my ICM

Its a 04 BEL engine no icms

I've got a 02 a6 with the 2.7t that I've chased this for awhile now too... I did the 2.0 conversion and everything was fine for about six months and then when I got on it hard it would misfire but wouldn't set a code. Popping out the exhaust. well I could change the plugs and it would go away for a week or so... I noticed brown "etching" down the side of one or two of my plugs and wrote it off deciding to change the plugs AGAIN. Well it started missing almost immediately and I rewired all of my conversion again soldering all the joints this time. I figured for sure this would get it fixed... NOPE. Well I bought 2 cards of dielectric grease and greased the connectors and the boots where they plug into the plugs... Guess what? $2.75 fixed my problem. The coils were arcing down the body of the plug and sparking to the sidewall of the plug well! Try it it might work for you