mtxplorer, dont rule out that it is your patch cables. Often times this is the main source of noise entering a system. Try this:
Disconnect the patch cords from your amp. Insert either the left or right side of a spare patch cord into your amps left or right input jacks. Turn on your system and your engine. If the noise is gone, reconnect the your patch cords to your amp, and disconnect the patch cords from your in-dash reciever. If you still have noise now, its definitely being picked up by your patch cords. Try re-routing your patch cords. Are your patch cables the twisted pair design? These are the best in noise suppression. The noise could be also coming in through the speaker wire. To test this, disconnect the speaker wires from your amp. Start the car. If the noise is still present, then it is being radiated directly into the speaker wires. Move the speaker leads. The noise could also be coming in from your electrical system. Try filling your battery with fluid. Your alternator mitght be acting, or you could just need a good ole tune-up.
Make real sure you have a good ground. I used the bolts that hold the back seats down. Scrap away the paint and bolt your ground down real tight. Also, make sure your amp housing is isolated from the car chassis ground. Mount the amp on something like a piece of wood or your speaker box. I hope some of this helps....
Later, Jason
