Can I replace just the front two sensors?

The rears don't need to be replaced 'cause they only keep an eye on what the converters are doing, correct? Am I also correct in that the PCM uses only the front O2 sensors for its calculations?

The car is running pig rich and I figure its a pretty good bet that the original 94,000 mile sensors are shot. No sense in replacing the rear sensors if there is nothing to be gained.

Is the correct P/N for the sensors 25312184? If I do have to change the rears they use the same P/N right?

Thanks

 

Yes, you can just change the fronts. Yes, only the front sensors are used to feed back the A/F ratio info so the PCM can make corrections.

I believe the connectors are a different shape on the pre-cat and after-cat sensors, so the part numbers are probably different.

 

before the cat are FLAT PIN connectors and after the car are SQUARE PIN connectors... Now if I can just find my damn O2 SIM on the drivers side...