02 sensor

[dragster557]

Have you ever known some one to change this sensor and help fuel milage when there were no codes showing any problems.Thanks

 

[Spowerback]

no
you can always check it by yourself by connecting a multimeter and measure the ohm

 

[disciplerocks]

Nobody ever thinks about the O2 sensor until there is a problem, but you are supposed to replace it every 50,000 miles for older vehicles and around 100,000 for newer (with OBDII). Replacing it helps keep the correct info about your A/F ratio and helps keep the cat from crapping out early.