Currently 87k on the clock. I drive 20,000 miles per year. If I gained a 1mpg increase it would pay for itself in 18 months. I know many things can alter mpg but this is one I’d like to know if it’s worth it.

Cost for me for all (4) O2 sensors installed is $300.
1 mile per gallon increase would save $200 per year.


Has anyone ever replaced any of the O2 sensors and noticed an improvement in gas mileage? Just curious.