Where is the cheapest place to get a downstream o2 sensor? Local stores (pepboys and such want 75 bucks....)

 

Just bought one myself from www.oxygensensors.com. Downstream was $59.99 for the OEM part, and shipped for free. (got it two days later.)

 

alternative: get a o2 sensor simulator: 30.00 plus shipping
search ebay for oxygen sensor simulator.
that is what I did. Ask how to fool the oxygen sensors heaters as well, else the CEL light will remain on.

 

Do your o2 sensors being bad effect your gas milage or your performance?

 

The 2 front ones, yes. Not the rear sensor. The ECM does not use the signal from the rear sensor to manage the air /fuel ratio or other engine ignition systems. It's only purpose is to confirm if the catalyst is working allright.

 

oh i wasn't even thinking about that one thats not an o2 sensor i think, its something else, mine's been disconnected for 2 years and i never got a cel for it (i've got a test pipe)....

 

Maybe your model year does not monitor the rear O2 sensor. In my 1998 it definitely does.