Should I replace 02's?

[pitbulldell]

I have a 95 Ex and I had over 400 thou miles on the original motor. She finally got tired and I replaced the motor a lil over 2 years ago with one from a salvage yard. New motor runs good , My question is should I replace the 02 sensors? I have replaced every other thing on this truck though out the years as I have had it since 2000. IAC,MAF,TPS,EGR, EGR CONTROL MODULE,PLUGS, WIRES, ETC all have been replaced at some point but the 02's are still the originals.I ask because gas milage is not looking as good as it has before and thats the only thing left that is not new.

 

[bilzy7]

I found on mine my clamps on fuel filler neck were loose. O2 sensors if they are failing, if not I don't see a big improvement... If you want go ahead can't hurt, those are some old ass sensors if you got 400k+ new motor miles on them. Im replacing mine soon and my 98 is at 125k mikes.

 

[jremington59]

I could be wrong, but I believe if they aren't performing within specs they will kick the check engine light. Preventive maintanence is good but at their cost replacing them may gain you nothing.

 

[dcdyd]

I will wait until the check engine light is lit. I changed two bank1 sensors on my 98 EB 5L until the check engine light is lit and didn't see mych mileage improvement. The biggest mileage improvement was seen after I cleaned MAF sensor. The mileage increased by 1 mpg.

 

[SoNic67]

In my Sable I did replace the pre-cat O2 sensors at 179k miles and I saw a small improvement in mileage. I think they are slower and slower to react, before they finally fail.
I did try to do the same to my Explorer but they are solid rusted in the exhaust pipe, so I cannot say nothing about that.

 

[dcdyd]

When you are ready to remove it, run the truck for 2 to 3 minutes. Just be careful not to burn yourself. It is much more easier to remove it that way. I replaced both pre-cat O2 sensors at around 120K original miles.

 

[pitbulldell]

how many 02's on my 95 EX 4.0 OHV. Just got the urge to change them since they got almost a half million miles on them, And I found a $35 dollar off coupon from couponcabin that I can use.

 

[YMMV]

You can remove them and clean them if you want. No point in replacing them if you arent getting any 02 codes/heater circuit codes. If you do decide to replace them/pull them, put a little anti seize on the threads.

 

[SoNic67]

how many 02's on my 95 EX 4.0 OHV. Just got the urge to change them since they got almost a half million miles on them, And I found a $35 dollar off coupon from couponcabin that I can use.

Just replace the first two pre-cat. the one after the cat are for monitoring cat.