I see this alot shortly after an install (of course it always is from the "other" shop that the customer has now gotten fed up with and wants you to correct their mistake for free). Check the power connection at the battery. Especially if it is a GM with the added on side mount audio lug adapter for the battery. Many installers tighten up the locknut and twist the cable around to where it now has bound up tension. Once you drive a little, the cable pulls and loosens the nut causing amps to clip when power peaks hit. Also, check the fuse block (usually underhood) to be sure it was mounted properly and the ends aren't pulling out of the caps (usually see black burnt marks on the ends of the fuse). If it was working properly a month ago, most likely you are ending up with a loose connection (also check ground cable to body to make sure it is still tight). One month comebacks are almost always a "not so good" connection that reared its ugly head after a few weeks of bumps.

Matt/MCOR