I have been having an extremely rich condition which my friend and I thought was a bad O2. Well we were right. When I turn the car on the passenger side O2 goes to 190mV, but it never changes. The drivers side O2 starts out at 200mV and the proceeds to shoot right up to 900-920mV range. Will one O2 not working cause the opposite bank to run full rich? Also isnt the O2 supposed to cycle up and down because mine seem to hold constant right in the 900-920 range. Both O2's are brand new also so I dont know why one is not working. Anyone got any ideas?

 

sounds like you have some fouled O2's. did you do the heated O2 conversion? if you havent, i would check it out.

how long were you running the car when you observed the 900-920? when O2 sensors stick..that does mean they are bad. as far as staring out at 200mV, i dont know what to say. mine are heated and they both start out at abotu 450mV so you could have a problem or its typical nonheated O2 functioning.

 

Anyone else I am probably going to convert to heated O2's, but any other thoughts.