I have an aftermarket head unit and for a while, I've been having a problem with the AM/FM radio. When I listen to CDs, the music is fine, but when I use FM mode, sometimes the music sounds like it's cutting out. I mean, the quality would degrade while driving around and sound like a speaker problem. But I know it isn't a speaker problem because AM/FM would sound fine when parked and the CDs sound fine when driving around. I don't think it's the station's frequency because it sounds fine in the van and the van's radio reception is more "picky" than my car. Could it be that I pulled the antenna cable out of the mast a little bit when installing the stereo?