Not sure what part of the country you are located but I have been experiencing the same thing on a colder morning. I live in CO now and I have actually been told by a fellow A6 2.7T driver to use lower grade fuel. He did and the issue went away... Not sure yet if I want to do this since I am using the APR chip tuned for 93 Octane...
I am going to get with RS Motorsports in Arvada, CO to confirm and maybe have the chip retuned to 91.

Good luck.

 

My old car use to do that but it was because of some of the seals, they were old. So I replace all of the one that I think would be a problem to the fuel injection and that fix the problem.

 

Did you find anything interesting in the diagnostic documentation?

 

i have a 2000 2.7T and it does the same thing when my car idles... Its weird, my car dont have a bad idle during cold engine... ONLY when the car gets warmed up after driving a while on the road, everytime the car idles pretty bad.... like shaking.. not as bad though.. last time i went into the dealership, a mechanic told me that my #6 cylinder might have a misfiring... bleh.. dunno... my major maintainense is coming up @ 90K to the whole thing... so hopefully it will be better... any suggestions or anything guys??

 

If you are still having the problem, I'd recommend changing the air mass flow sensor. That fixed the problem on my 2000 A6 4.2.

 

I have the same problem...01 A6 2.7. With cold engine, at start up, sounds like an exhaust leak for about 15-25 seconds. If I try to drive off, there is little or no throttle reponse and stays in 1st. If let it warm up, no problem... summer or winter. Only does this about 80% of the time.

 

Mine kinda does this too, it is louder, then all of a sudden it quiets right down. I think its normal, and is likely the turbo's waste gate opening up to prevent over pressure. (Cold turbos produce more air pressure than hot ones.) 25 secs later, its normal. If you are in a really cold climate, it might stay open longer. I wonder what the car will do at -20, be interesting to see this winter.

The staying in first gear is normal, the owners manual mentions this when its normal. my mercedes said it too only they described it as "When cold, the engine may make additional noise when driving.) I took this to mean the engine will rev higher. They often do this for pollution reasons, it heats the engine faster to produce less emissions sooner

All and all, you REALLY should try and let ANY car warm up 1-2 minutes before your drive off. Its hard on an engine to start em, slam em into gear, and drive off when they are cold.

 

Per the suggestions, I have been running lower octane fuel for some weeks now (87 and 89), and have also used several fuel system cleaner additives (like Techron), all to no avail. I still have that first-few-seconds rough idle, then everything is fine. So, today, I took the car into my mechanic for a full fuel system cleaning, where some machine cycles gasoline with some strong cleaner additive around the the fuel system for a couple of hours. We'll see tomorrow morning if that did it ...

 

(P0302) cylinder 2 misfire detected but the next code tells it all (P0300) random/multiple cylinder(s) - misfire detected, things to look/check are spark plug(s), plug leads, injector(S), ignition coil(S), low compression, wiring, also another point is low fuel level when this happens as a lack of it will cause a misfire

 

KC- the 2.8s have been know to have bad injectors, check to see if it has purpleish injectors

For the 2.7 people i recently had a car with this problem, but was also coupled with extended crank

and the problem was a leaky #2 injector so that would be something to look into(but it was not leaking enough for a residual fuel pressure test to uncover, because of heatsoak)

And for Avant the random/multiple cylinder code is always present with a cylinder specific misfire code just for your knowlege