Rear deck rattle?

[generic808]

I added a Fosgate 10" sub and I'm running it off of a Fogate 200.2 amp. Every time the bass hits, there's this horrible rattle coming from the rear deck. I even notice it when I hit small bumps in the road and it's starting to irritate me. I'm planning on replacing all the OEM speakers with Polk's this weekend, but was just wondering if anyone else has experienced this? If so, what was causing this rattle. If need be, I'll dynamat the whole rear deck, but I really don't want to spend $50+ for insulation that should already be there. Has anyone fixed this rattle?

[prlwhitecoupe]

i was planning on getting a JBL single 12" GTO series sub already in the enclosure.....i love how it looks...but ive been questioning whether my warranty on the stereo or otherwise be void once i do sumthing like dat.....also if im gonna get the same probs....im not so sure if i wanna get it.....but i was planning on getting dynamatted neways as well the license plate....cause since it only has two screws to hold it it already rattles with the factory sub....

Can u describe how u installed ur sub? and amp?.....is it hooked to the factory system? i have the bose 9 speaker, you too??