any gm techs on here??

[54Caddy]

Have a 2001 yukon with a radio problem. When driving over bumps it will make a poping noise threw the speakers, when it happens the music will still play but it just makes that noise, even at times when it happens the display on the radio will go blank but will return back with correct time and all. I am thinking there is a wire shorting out somewhere or the original deck is just messed up it also wont play cds. What you guys think??