I have the same problem......never fixed it. Cd mode sounds great, but I get static on the radio.

I just put a screw in a random location for the amps ground (rear upper metal deck).

5 speed MTX /KKM Custom Intake /Dynomax Super Turbo /TH Fix /Audi A6 Sidemarkers / Badgeless /Audio:(JBL600.1 amp,Polk Dx Subs, Infinity 6953i 6x9's, Lightning Audio Strike Cap)