This happend to my friend and the way it was fixed was a new sub cuze he had blown the other one. This sounds like the same problem you have so a new sub will fix it i am guessing.
98.5 Black SVT with 34k miles Build #5683 Born on 4\15\1998
WR Headers GMK CAI
Blaupunkt system fiberglass tweeter pods
L.E.D. tail lights in the works
