check your grounds? go through everything again and make sure that where your ground is for your amp is in a suitable place, NOT grounded to some metal that is paper thin. make sure you ground to somehtig that is decently think and where its grounded at make sure you use sand paper and sand the crap out of the spot so its BARE metal. maybe pull your head unit out of your dash and make sure that when you spliced your wires together to the harness that theres no bare wires touching each other, wire caps and or electrical tape work good. also make sure your rca wires are not running on the same side as your power wire i rn power on one side of my car and rcas on the passanger side. that can cause static and unwanted noises.