Years ago I fussed with JUST replacing the suspected bad O2 sensor... seemed to always still give me grief

Once I gained a good understanding on how the sensor worked, the tight calibrations of them, and how the computer used the info I decided that once one proved to be bad (Usually between 45 to 80K miles) It was time for a new SET of sensors.....

I know this is an more expensive method but it has served me well over the last 30+ years of computer controlled motors..... I am also eternally grateful that this is a part the aftermarket stepped up to the plate and made....

Early O2 sensors on one of my low tech 1975 Nissan motors were in the $159.00 range and I needed 2 of them...arrrrgh! Same part in a auto store today is under $60 bucks.... much easier to swallow