I have shielded RCA's
And my amp is grounded in the trunk on one of the studs for the trunk latch. Its weird because at first it was grounded with something else (I think the tail light ground) so i moved it to a stud with nothing. This FIXED the interference and everything was sounding perfect for about 30 minutes till it slowly came back. There is some white paint back there so I definitely will sand that down tonight and see what that does.
And what do you mean by earth ground?
Thank you for all of the help everyone.