Well i am a cheap *** i dont want to buy two o2 sensors b/c my car only has 51,000 miles. I heard that the front o2 tells the computer the air fuel mixture going throught the exhaust and the o2 behind the cat just tells the computer that the cat is working. So if i just change the front o2 sensor would that help my gas mileages out?? It has been real good lately. thanks

 

What year is your car? (A "signature" with basic info like that is a big help, if you want questions answered).

93-95 have 2 sensors, both in front of the single cat. 96-97 have 4 sensors, 2 in front of the dual cats and two after.

It isn't likely that 51K miles would kill the sensors. What problems, if any, are you trying to cure?

 

It is a 93 what i am doing is tring to get better gas mileage. It never got anything high then 14 miles to the gallon. I will baby it and it will get 14 mpg then (lately) when i run it hard it still gets 14 mpg.