I have a 2004 conv w/ the Mach 460 system. It sounds great when its working right, but I've had an issue with the subs cutting in and out, random popping sounds and the sound constantly changes. The changes normally happen after hitting a bump. It may sound fine, but the moment I hit a pothole, it pops and I have no bass! It also gives off a feedback sound most of the time.

Anyone have issues like this or have any suggestions on how to fix it?

 

I used to have issues like this in the system in my pontiac. Try to see if there are loose or weak connections anywhere. If they are loose they could be coming apart during those big bumps.

 

sounds like you have a bad connection. Power the radio up and then try to wiggle the hrns's going to the amps to see if you can isolate where it is loose.