rockauto has some good prices for sensors... as far as I know the front and rears are NOT the same...tried it once and it didnt work correctly. I would switch them left to right (fronts) to check for a faulty one, if the unresponsive one moves to the other side when you switch them you found your problem.

 

Sorry Richard, but this is FALSE. They are infact the exact same part number. It is possible, that you had a bad rear sensor also, and swapped it into the front, and still had problems. I've swapped them for people in the past, and it works.

Here's CarQuest's dealer catalog, upstream and downstream are the same part. I'll be deleting these pics in a few days since they show dealer pricing...



Tom, swap the sensors, like we talked about. Save your cash. Turn off the rear 02's in your tune, swap the bad sensor to the rear. It will be just fine.

 

Not all of them are the same.. some year models have different connectors on the front 02s vs rear 02s.

 

^^ That's correct, but in 2004, they are all the same.

 

oh ok i see what your saying... guess i should have put the years on there

 

There have been very few times when I've seen bad gas mileage that wasn't caused by a bad O2 sensor.

*This doesn't include towing or heavy modifications.