Thanks for the feedback, but I should also mention the other part of the test. When I disconnected the green wire and connect the positive of the tester to the end leading to the O2 senser and the negative to the ground. I started the with a warn engine, I see the voltage started at about 0.7-0.8 but then continue to drop steadily to less then 0.1. I race the engine speed to 2,500 rpm and the reading droped to about 0.03-0.04 and did not bounce back. The cooling fan was on indicating the engine was fully warm up. Together, do this mean that the O2 senser is working alright, but I probably have a bad vacuum leak somewhere which cause a low voltage output?
Leo

It means it is working and doing its job.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
Of Leo Lee
Sent: Saturday, April 23, 2005 1:24 PM
To: vanagon@GERRY