I had the same problem and it turned out to be the fuse for the radio was loose in the fuse block. Replaced the fuse and no problems since. I would hit bump and the radio would cut out. Hit another bump and it would cut back in. All my wire connections are soldered so I did not figure a loose wire connection. The fuse was not blowing so I was stumped for a little while.

 

I cut the ground on the truck harness and wired it up to a bolt inside the dash. Still did the same thing. Then I decided to take out each speaker one by one until it stopped. Kept doing it. So then I snipped all my tweeters(cheapo's off ebay) and found out it was the wire for the tweeter on the passenger side door grounding out because the insulation wore away. Problem solved... Proccess of elimination. Thanks for all the help guys

 

No problem, never would have guessed it would have been a tweeter causing all that problem.

 

Me either. That's why I didn't even mention them lol.