I have heard in many circles to replace the O2 sensors at 100k miles. I have an 02 screw,5.4, and I think this truck has three or four of these cursed things. I don't really have any problems to speak of, but do I just do it for the sake of preventative maint, or leave them be? I average about 14 mpg, which seems about normal for my driving habits.
Any thoughts anyone? A local reputable mechanic tells me leave them until there is a problem or code.

 

if you arent having any problems. i would leave them alone

 

you should change out your front o2's every time you change your plugs

 

I did just replace the plugs, thanks for the advice.

 

if you want to try it go ahead but its a large PITA, i tired mine like three different times, even got the special socket for it and i finally busted them loose with an open end wrench. just dont strip them. fight them till you get them off. but really if your happy the way your truck runs and with the mpg your gettin then just leave it. just my 2 cents.
Scott

 

if they are being a pain just hit them with a torch, even a plumbers propane type and they should spin right out. worked for me.

 

Yes. And I agree with the mechanic.

That's what the check engine light is for. Takes the guesswork out of preventative maintenance, for the most part.

Oh, yeah, the rear 02's after the cat convertors...they only monitor cat function. They take no readings worthy of being that careful or picky with them.

So, even replacing the front two sensors may indeed be overkill right now.

 

Any particular reason? Not trying to start an argument but I have never been recommended to do that and nor do I follow that logic. Especially at $150+ for the set! When O2 sensors go, you get a code. My next question is how often do you change your spark plugs and what kind do you prefer to use?

 

my truck ran good at 123k with the original sensers. i changed them and and picked up another 3 miles a gallon. just the ones before the cats, nevermind the 2 rears.

 

^Thats why. Your sensor becomes lazy and doesn't work properly any more much like the spark plugs that wear out also. You could wait for a miss fire code or you could just do some preventative maintanence and replace them. You should be able to get the 2 sensors for less than a $100. My dads old ranger wouldn't start the one day because the o2 sesor took a chit on him