yep, I had an exhaust cat fail on my '92 Camaro Z-28...of course we didn't find that was the problem until spending countless hours trying to diagnose the problem...GM replaced throttle body, 'puter, everything...the car would just quit with no warning...had to be towed 3 different times...finally long after the warrantee ran out, I was in the garage, moved the car out, heard a rattling noise, like metal in the exhaust...cat had rusted out, plugging the outlet just enough at times to shut down the engine...puters..GM researched all that had been done, replaced it even though it was out of warrantee due to the 5 yrs emmissions clause...so go after these guys and tell them to fix it..