My brother-in-law has a 2002 Camaro 5.7L V8. He had a custom exhaust put on and this is what they did. They removed any catalytic converter and (2) O2 sensors, I believe the 2 remaining they extended the wiring , but I can not be sure which set of plugs they plugged them into. His problem is somethimes it starts fine other times he can't get it to start. He did say they erased the 2 O2 sensors from the computer module. Any ideas?