ndoe

Hi I'm new to this group & A6's (owned for 3 months).
I've an intermittent problem at motorway cruising speeds where a rumble & vibration starts and gets stronger and louder over a period of 10 seconds, it feels as though it's coming from beneath the passenger seat (right hand drive uk spec). If I lift off the throttle a little and reapply it goes away, it doesn't matter if I'm in auto mode or manual selector with 6th gear selected.
The cars covered 37000 miles, is a 2000 saloon, everything is stock audi. I've had it occur with and without cruise control enabled.
It only seems to happen after a prolonged period of contant speed on a motorway. I've got a years warranty remaining but fear they'll not be able to reproduce the problem. I can drive 5 days in/out of work and it will happen maybe twice.
Any ideas ?

regards
nigel

rdynamix

If it is a metal rattle sound it may some exhaust part or heat shield that is lose. It could also be a cracked catalytic converter (inside crack).

There is also the infamous vibration at 50-55mph
which does not sound like what you describe.

If it is not a metal rattle I really have no idea.

Try a search<ul><li><a href="https://www.audiworld.com/search/">Link to search page...</a></li></ul>