EricAl

My new-to-me 08 S6 (23k miles) has a most annoying off-idle hesitation. It occurs at about 1,000 rpm under gentle throttle. When the hesitation occurs, I often add more throttle and then over-control. (Oh, what I would do for a manual transmission). It is especially annoying in heavy traffic.

Dealer has checked a couple of times and has reprogrammed the transmission computer which improved things but only slightly.

Have any of you experienced this stumble? It seems to me an engine problem, maybe injectors, not transmission. Any solutions??

Eric
(84 Olympic, 95 S6, 08 S6)

chuckee98

With engine cold or warm? Possible Carbon Deposits / Build-up on intake valves - may need to decarbon them with 1. chemicals ("throttle body cleaning" as offered by the dealer service department) 2. disassembly and mechanical cleaning of valves. Worst case.

Just a guess, since direct injection engines are known for this.

DirtyVegasTT

I was told by an Audi tech friend of mine that no one with an S6 has been witnessed with the carbon buildup in the engine. Plus, with only 20K on the car I don’t think that it would the issue.

With that said, there were some service bulletins for S6. Has your car had all of them performed? I remember something about a coil pack.

In a worst case scenario, if you are not getting anywhere with this dealer try another one. So far the only issue I came across was a tranny one that I did a write up on a while back.

https://www.audiworld.com/forums/sho....php?t=2749449

chuckee98

I hope you're right. I still plan on having the throttle body cleaning done at my next oil change (prior to it) just as preventative maintenance to avoid this issue if it does arise in the future. I experience an off idle stumble when the car is cold, which smoothes out when it's warmed up. This I've heard may be a symptom of the early stages of carbon buildup. 95% of my driving is short duration local driving, which is not a good scenario.

I've read of issues with carbon buildup as early as 7500 miles (IIRC), but this was on an B7 RS4.

2008A6

Vegas - i read your previous tranny issue.. I went from an 08 3.2 to the 07 S6 and on the S6, there is a very noticeable lag when engaging Drive from reverse. The car keeps rolling back a bit before Drive is engaged. My 3.2 engages immediately..
Is that normal on the S6? The car is going in for coil pack recall tomorrow.

DirtyVegasTT

Mine rolls back too before the D kicks in after the shift on an incline, but I monitor that and am very gentle when going from reverse to drive by not hitting the gas and using the breaks. Doesn't really bother me as it only happens when pulling out of my drive way.