Help With wiring..or something else?

I have a 99 Rodeo LS and i'm having a little problem with speakers. When i give a hard turn or i drive on a bump, my speakers stop working.:banghead: And the CD is not skipping because i got my i-Pod connected to it via an interface. I checked the wires behind the CD player nothing seems to be crossing. Plus i know is not the i-Pod either because it won't work on Tuner or Cd either. It use to happen with the stock stereo too so i know is not my Cd player. All i can think of is a wire rubbing somewhere, any other ideas? Has anybody had a similar problem? All help appreciated. Thanks!