My 1980 242 Lambda Sond dash light comes on from time to time. It does not effect the drivability of the car though. I've already replaced the O2 sensor (no change). Is there a long laundry list of other causes for the light? If not can somebody tell me what the next step should be? I don't have a Bently book for this car. The Chilton and Haynes don't address the issue. My mechanic when checking the emissions said the CO level went in the opposite direction when the O2 sensor was disconnected. That had him baffled. Might this be related? Jay