In preparation for a California smog test, I recently installed one of
Ken Lewis' oxygen sensor display tools. He makes and sells these for an
amazingly low price. I wired it in and mounted it in my dash cluster so
I could see what was happening with the fuel mixture while I drove. It
showed that my O2 sensor was sluggish and so I replaced it with a Bosch
generic single wire. This improved the readings greatly so I did a few
more things and went in for the test. Passed with ease. Thanks Ken!

http://neksiwel.20m.com/photo5.html

Mark