Factory sub popping/buzzing with key off/on

The sub in my truck pops/ buzzes when I start it up or shut it off. It usually has about a 3 second delay before the pop on start or buzz on turn off, from the key turn. Also when after the truck has been off for a few hours if I go back and touch the Amp it is still hot.

Any Ideas on what is going wrong here? Or how to check for problems? Right now I just have it unplugged

http://powerstrokearmy.com/forums/showthread.php?t=25167

Should be in there.