noise noise noise

[mexicanzero]

sorry if this has already been asked but i did a search and did not find what i was looking for.
so i have a Rockford Fosgate p200.2 amp (bridged) and a cheap 10" thump sub.
my car is old but works really well and has relatively low mileage, its a 1992 Subaru legacy but the alternator is almost brand new and the battery is probably about 3 years old.
i have a pioneer deh-p5800mp
i have the rca wires (far from top of the line but not the cheapest possible) on the right side of the car and the power wire (8 gauge) is on the left side.
the amp is grounded with 8 gauge wire to bare metal on the floor of the trunk is this a bad spot since the metal isn't that thick?

i had an amazingly awful whining sound that went up with rpm's which is what convinced me to change the rca's to the opposite side on the car. it seemed to be gone... but wasn't

lately when i pause my cd i wont hear anything then i'll go over a bump and my sub will thump as if it was getting signal and then the whining which increases with engine rpm will come back then i will hit another bump and the whining will go away again.

this happens intermittently almost as if it just feels like doing it.
my head unit is grounded using the wiring harness, some people have told me to ground it to the same spot as the amp. should i bother?

i have not checked the alternator wires since they are hidden and would require removing a lot of components to get to. the battery grounds looked dirty so i loosened them and moved them around just in case they weren't contacting properly.

i have troubleshooted it a lot: when i unplug the antenna nothing changes when i unplug the rca cords from the amp its gone and if i unplug them from the head unit the noise is also gone. this led me to think it was coming from the power wires of the head unit so i installed a couple of noise filters, they didn't change a thing.

i have spent way too much time on this without success so please tell me what to do!
thanks a lot
-Alex

[speedoboy31]

check your amp ground. if no problem there, sounds like a possible problem in the amp. try it in another car?