I have an 04 A6 S-Line, automatic w/ 34k on it. The car is all factory without any mods. Fortunately, it's still remains under its original factory warranty but that's expiring soon. I've taken it to the dealership twice over this issue and it's about to go for its third time.

The problem is that the car bucks/hesitates/surges during acceleration. This is most prevalent during moderate acceleration. During light acceleration it isn't detectable and during heavy acceleration it's minimal. It occurs most around 2 and 3 RPM. This also occurs when going up hills I can even see the RPM guage coinciding with it as it fluctuates. I'm not getting any check engine lights and the dealership claims it's error code free. So far on visit 1; they replaced the plugs. I had to take it back shortly after as it was back to its old tricks. Visit 2; they replaced a coil that they claimed was bad. Interestingly enough, on both occassions the car ran perfectly for a few weeks afterwards when it would gradually worsen and be back to its old tricks. I guess it's possible that there's a computer and or sensor that's on the brink of going bad and maybe they're resetting my computers when it's being serviced that makes this work for awhile? This is my work commuter car so I'm driving under the same conditions every day. One day it drives beautifully and the next day it's feeling tempermental and I buck away to work. I've also observed a slight fumey odor emitting from it in my garage on it's "bad days" while when it runs well there are no fumes whatsoever (fumes seem to come from engine comparment and no evidence of leaking etc). Is it possible this could be the 02 sensor?

Any help or advice is greatly appreciated. I'm trying to educate myself a little before taking it back to the dealer once again. I'm just hoping they catch it on a bad day!

 

Did they make FWD A6 Sport packages? I know my FWD drive a6 bucks alittle if that's what you want to call it, but not up hill.

 

I have 06 model and had an issue..I ended up taking that in 4 times...finally test drove with shop foreman and got lucky that problem showed up during test drive. I would recommend doing the same if you havent done that already.

 

Good suggestion on taking the mechanic along for a ride. I may need to do just that. Do you recall what you're problem ended up being? It's just very frustrating that it's consistent enough to be a large annoyance on my part but inconsistent enough I think the mechanics think I'm a nut job. I really love my car and how it drives when it choosed to have a good day. Just wish everyday were like that!

In regards to the other post of whether it's front wheel drive or not, it's a quattro 2.7T. We don't see many front wheel drive models here in PA.

 

where are you in PA

 

Pittsburgh

 

o thats far im all the way about 15 mins outside philly