I have a 2003 A6 quattro 3.0 v6. I just got it with 94k on it and it has been driving good. Since I picked it up I have noticed a Oil burning smell when I was driving. I keep checking the oil level and it has not gone down. I just did a tune up and replaced 3 coils and all the spark plugs. I had a code for multiple misfires and it called out 3 cylinders so I replace those coils. Anyways back to the issue. I think it has a slight leak on the valve covers and it drips on the manifolds? It was smoking a little yesterday after a long drive. You could only see the smoke when you raised the hood imediately after driving. Any ideas what wrong? Valve cover gaskets?
Oh and by the way Great forum!!

 

You may want to take a look at the oil pressure switches and around the oil filter as they have habit of leaking as they age.

 

I was having this same issue with my 04 3.0 quattro. I could smell the burning inside the car and could also see smoke that would quickly dissipate when I opened the hood. The culprit was indeed the valve cover gaskets, which were recently replaced along with the timing, t-stat etc., but the mechanic did a poor job. Took it back in and had him re-install new gaskets. No more smell or smoke and its been over 6 months. Of note, I could see the oil stains along the valve covers, mainly toward the rear. Oil was dripping on the exhaust and burning up. I also cleaned the hell out of the valve covers and removed any oily/dirty gunk stuck in the bolt heads and anywhere else I could see just to make sure it wasn't old oil residue burning up.

Hopefully yours will be as easy a fix as mine. Good luck.