I have a 2006 S4 with 45,000 miles and I am bring it in for service for 2 issues. If the car sits for a couple of days when I start it I get a knocking sound for a few seconds from the front of the car. It is not valve noise but a much louder sound. It is still under warranty and I want to make sure it is checked out before the warranty expires. All service done by Audi.

The other issue is when I go down hill on my driveway one of the lights starts flickering. It only flickers when I am going down my steep driveway. Any ideas. Thanks