Is it likely my Pontiac Firebird O2 sensors are bad?

I have been chasing a mis-fire condition for about a year. I have replaced two cats three sets of plugs/wires and the ignition coils in the process. The mis-fire is finally gone, it was due to plug wires arching and damaging themselves and the ignition coils. Now the only OBD II codes I get are for Auxilery Emmisions Control, with no details. If the cat can over heat from a mis-fire can O2 sensor over heat for the same reason. Any other Ideas of what it might be, I also intermittently pull a EGR flow code. But many people tell me its probably ok. Please help.