Why does my Audi A6's engine suddenly rev up while idling?

I have noticed that after driving for a while and coming to a complete stop, my Audi A6's engine will sometimes start revving up for a few seconds before settling back down to idle. This only happens occasionally and seems to go away when I turn off the A/C. Can someone shed some light on this issue?

This could be due to a faulty idle control valve, which regulates the air flow into the engine while idling. When it becomes dirty or stuck, it can cause erratic idling behavior. I recommend having it checked and replaced if necessary.

I had a similar issue with my A6 and it turned out to be a problem with the throttle body. The electronic throttle control system can sometimes malfunction and cause revving while idling. Have a mechanic check the sensors and connections for any issues.