[Mr.ac]

So all factory radio?
No subwoofer amp or other add on's?

If there are add on's then their is your problem, you have a loose connection or something is shorting out.

If all else fails take out the stereo carefully, and check that all the wires are plugged in properly or if some one did a hack job and return to stock.

If that doesn't work, then a trip to any car audio place might be in order. Good luck.