2000 gmc rcsb 5.3 programed.
I want to cut my cats out and put x pipe and my flows back under. But i didnt put the program in my truck so i have no idea what kind or what they programed. So if they didnt set it to run without cats it is goig to make it run like crap???

 

No it will just throw a check engine light.

 

just go get a retune and have them turn off your rear o2 sensors...but you can run without them turned off and it'll run fine but it'll make your check engine light come on as stated above..

 

Depending on your tune, it could also cause a slight drop in fuel mileage, but who cares about that right?

 

How could i get the tune thats in it now?? I want a custom tune but my computer will be locked right?