I noticed a rattle in the dash the other day and traced it to the ashtray. When I hold the ashtray in, the rattle stops.

Has anyone encountered and fixed this?

As I recall from my old (but not forgotten) 1998 A6 2.8Q, the wood trim on the ashtray is held in place by two plastic clips/pegs at the bottom that can snap or sheer off, leaving the trim hanging from the lip insert at the top of the ashtray's face. Don't know if this is your problem, but it could cause the trim to vibrate against the ashtray housing. I had to crazyglue the sucker when it happened to me. Good luck.

Yes - I have it too. Dealer tried to fix with out pulling the Radio cluster by putting some foam somewhere. Its better but is still there. Someday they (I hope) are going to get me a radio that doesn't drift and when they pull things apart for that I am going to address this again.