I just purchased a 2000 Camaro Z28. It has slp headers feeding catalytic convertors. My check engine light just came on and my Autoxray says " o2 sensor heator circuit malfunction (bank 2 sensor 1). Since my cats have a o2 probe in front and back and on both sides, I don't know which one to replace. I've ordered shop manuals but haven't received. Can anybody tell me the location of bad probe. Any help would be very much appreciated.