To detect the voltage deliver from the O2 senser to the ECU after engine warm up, I connected the positive end of a voltmeter to the green wire coming out of the O2 senser, and negative to the ground. After engine warmup, I observed the voltage. A higher voltage (0.7- 1.0) indicate a rich condition, low voltage (0.6 and lower) means leaner condition. I found that the voltage continue to fluctuate between 0.2 to 0.8. Can someone please tell me what is this mean?
Leo, 1991 multivan.