So I have a 2001 SS Camaro, bought it last year and it came with a Diablo Predator handheld with I assume the performance tune installed, I think the previous owner got it because he had 4.11's put in and needed to change the speedo. Anyways I've had codes for the drivers side o2 sensors last year so I replaced both, the heated part was the problem. So now last week, the p0420 came on, so I figured the cat went bad or the o2's on that side went bad too. Cleared the code, drove 3 days and it came back on, checked and now it has p0430 and p0420 codes. The tailpipes get a black soot after a day or two after cleaning, i'm wondering if the tune makes the car run too rich and killed the cats and 02 sensors, or if the soot is normal or having bad cats and sensors are the problem. Sorry for the long post

 

Sorry I don't have an answer for you but here's a Bump.

Hope you get an answer.

 

GM has so many CAT failures on those year F-bodies that they were forced to extend the warranty on them to 10 years and 120K miles. Yours going bad probably had nothing to do with the programmer.