I got this navi(Pioneer In-Dash Navigation/DVD Player Model #: PIO AVICD3)installed on the my 2004 GMC Denali and the sound quality is horrible. It sounds fine at first then start shifting sound from the front of the car to the back of the car. It sounds like someone is lowering the volume in the front then the back and vice cersa and continues to do it as long as the radio is on..It's very annoying. I took it back to Circuit City several times and they can't seem to figure out what's wrong with it. I also had a DVD system which no longer works. Has anyone experienced this problem that can hel
