i took my muffler off and ran straight pipe, and gutted my cats. is there a way to get my check engine light to go off, or do i need to put a muffler back on?

 

Its because you gutted your cats. You can either get o2 sims or get the code tuned out. Probably cheaper to just get it tuned out. I'm pretty sure the muffler don't have anything to do with it throwing a code.

 

^^^he's right. It has nothing to do with your muffler. Find someone around you with HPTuners or LS1Edit to get rid of the error or as mentioned you can buy rear O2 simms. The error is there b/c the rear O2 sensors are telling your PCM that the cats aren't working correctly.