[richtazz]

The factory speakers are probably bad. My 99 GT did the same thing, and it was the speakers. I replaced the factory ones with some nice Pioneer 6x9's and a $6 wiring kit so I didn't have to splice the factory wiring. To get ot the rear speakers, you'll have to remove the rear seat. There are two pull tabs that release the lower cushion (one on either side of the center hump). Once the lower cusion is out of the way, there are 4 bolts that retain the bottom of the seat back (2 10mm headed, and 2 13mm headed, the 13mm ones also secure the rear seat belts to the floor). Once those are removed, lift up on the upper seat cushion to release the upper hooks. You'll see some big round plastic retainers that hold the shelf carpet to the body, pull those out and the carpet and speaker covers slide off as one piece, which will expose the screws that hold the factory speakers in (5.5mm heads I believe).

Good luck