Why is my Audi A6 engine revving at idle?

I have noticed that when my Audi A6 is at idle, the engine seems to rev up and down on its own. What could be causing this and how can I fix it?

This could be caused by a number of issues, such as a dirty air filter or a faulty idle control valve. I would recommend taking your car to a mechanic for a diagnostic test to pinpoint the exact problem.

Another possible cause could be a vacuum leak in the engine, which could be causing the fluctuations in idle speed. Have a mechanic check for any potential leaks and repair them if necessary.

If your Audi A6 has a turbocharged engine, the issue could be related to the turbo itself. I would advise bringing your car to a certified mechanic who is familiar with Audi engines for a proper diagnosis and repair.