S6 V10 Misfires on Cylinder 6 only on coldstarts and really random. DESPERATELY NEED HELP!

A6 All/ S6 All
#62

Possible yes, likely not so much… between all the usual S6 tissues over the past 7-8 yrs I have found the single best mod I have done is remove PCV system/fabricate custom catch can and vent to atmosphere…

Also has every JHM item available, aside from their exhaust and or custom header… I purchased her with Milltech cat back… She hates cold starts, will barely run part throttle while cold. Drive 1-2mi and she’s fine… never ce light for misfire since PCV delete… Honestly car is a beast, after short warm up never any problems. Over 1 1/2yrs…

#63

I had similar problem … tried a number 0f things but finally solved when i bought and used a smoke machine to test for vacuum leaks on inlet system… in my case one throttle body gasket was leaking … these engines are very sensitive to vacuum or intake leaks . Best $75 i have spent to date …

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#64

@bjglen - Share the smoke machine you got. This could be another option for many as IMO you’re so right these motors are very very prone to issues with misfires and many areas where their is room for vac leaks.

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#65

I have just been dealing with this issue, believe it was also cylinder 6 misfire randomly at startup. Revving, driving ecu would not correct idle. Completely random about once every few weeks. Also sometimes would start fine and coming to the first stop sign down the street would start idling rough. As I did a bunch of work recently the other day went through the intake checking throttle bodies, cracks in hoses, the very last thing I checked was all the goodies on the front of the manifold and sure enough the vacuum purge valve on the front right of the motor the electrical plug was not locked on and as soon as I touched it pulled off. Probably one of the most common mistakes I see with audis is not part failures but human error. If electrical connectors do not click lock they will become your nightmare.

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