Dear aaallrighty, DJBybee, Klausc, Tooze,

Thank you for your replies. Each of you shared good advice with me. I was going to get the "CEL" scanned first to confirm that I indeed need an O2 sensor. However, thanks to the replies, despite the high mileage the CEL could be caused by a lose gas cap, or leaking vacuum line, etc.

I once saw an old O2 sensor that was replaced on this car or the other '96 850 I have and the sensor looked like a big spark plug. It had screw in threats with an electrical cord that traveled toward the engine compartment.

I'll confirm its definitely an O2 sensor, and if it is, take a shot at repairing it myself.

Question: If the 02 sensor is bad. Once I replace it, with the CEL go off automatically or does it have to be cleared?

Fellas, thank you for your help. God willing I'll be owning these cars for a while, and if I can learn how to make this repair, I'll save myself a boat load of money over the long run.

Hugh