mach 460 buzzing sound

Factory head unit or aftermarket?

I'm hoping that someone can answer this question. I have the same problem in my 94 cobra. Stock head unit, stock everything. The humming stops once the amps are unplugged. Both amps will cause the hum, but they won't do it all the time. Sometimes I can go a month without a problem then I have to unplug them again.

I've noticed that it will get worse sometimes with hitting bumps or when doing things like putting down the windows. Also, all the engine electronics have been swapped out, I've read that maybe a coil or the plugs wires can cause interference.

Thanks.