Factory FM Radio interference

[Vincent Torrez]

Hello,

I have a 2004 Chevy Impala SS with a factory CD player, iSimple Gateway iPhone adaptor.

the Factory installed Amp was replaced with an Alpine 4 channel, all speakers were replaced with Memphis Audio and i also added 2 Memphis Audio 10" subs in a sealed box, ran a 4GA Rockford Fosgate power cable from the battery, and ran a 4GA ground to the seat belt bolt under the rear seat (which is directly on the body) the Factory amp is still installed but the speaker wires go to the new amp. also each sub had its own amp.

ever since that unstall, my radio reception has sucked!!

if anyone has any insight, i would love the help.

also the car has 20% tinted windows all around and the antenna is in the rear window, ive checked all antenna wires and everything seems to be connected still.

Please HELP!!