i talked to bosch tech support about this awhile back. here's what he told me-the cars is warm and the o2 is switching back and forth. unplug the o2, let the car stabilize, then check the voltage at pin 3. once you get a steady reading, plug the o2 back in, stabilize again, check 3 again. the voltage should match, if not adjust the mixture SLOWLY AND FINELY, always, after every adjustment, blip the throttle wide open and let the car stabilize. go slow and don't adjust too much. this applies only to 84-86 201s with the 102 motor. also the 84-85 bmw 318s. good luck, chuck