its been 117000 miles and ive never changed them in the 80000 ive had her, think its a good idea to change my o2 sensors? nobody ever says how long you should go on a pair (theres only 2 on a 4.0, right? thats all i found) have a sneeky suspiction itll help my mileage.

ps- before or after a seafoam treatment? before, right?

 

i dont think you would need to change it if it hasnt gone bad..if its still truckin along then i think you would be good to go..

i could be wrong tho..

 

....if its not broke, dont fix it.....trust me, if its working fine now, leave well enough alone!

 

 

o2 60k-100k life Upstreams only. The downsteams monitor the cat(s).

old o2's may effect mileage

 

let sleeping dogs lie... if your 02 sensor was not working properly you would have a check engine light and poor performance

 

not nesseccarly a CEL but a drop in fuel economy and performance.