Hi all, I have an '87 760 GLE with the trusty B280F. I don't know how old the O2 sensor is. I'm guessing it's quite old, and has quite a few miles on it. What's the procedure for testing it? I'm guessing that I remove the connector, car will run OPEN LOOP, then with a volt meter set to milli-volts, check for change in voltage reading/ cover intake before AFM to see what happens to reading. I can't find any reference info on this subject. Thanks.