o2 sensors on 98 sohc

[fvumbaca]

I'm wondering if I should change my o2 sensors on my 98 4.0 sohc X, I have been searching through a bunch of threads and really cant find the answers I'm looking for.
1) when should i replace o2 sensors (I have 64k on my truck)
2) How many sensors are on my truck, the Haynes manuel isnt to clean on that and the threads i' read are a bit confusing as well
3) How much are the sensors
4) Is the repair worth doing to increase the longevity of my truck
5) I hear the front o2 sensors are hard to change, where are they? and are there any tips to do change them.

sorry about the long list I just want to know what i'm doing before i start the repair. Thanks

 

[Alec]

IMO you shouldn't change them unless you're getting O2 sensor codes and/or you have performance O2 sensor related problems.

I think you have 4. 1 on each side before the cats and 1 on each side after the cats. I think you have the dual inlet muffler system with the parallel cats?

O2 sensors are about $60 apiece I think, and I think they're easy to change, but that's just me.

 

[aldive]

Its a tough call whether to replace or not.

I would run several scans on their function prior to even thinking about the change,

The damn things can last and last or they can go South at anytime.

You do have 4 and they are far from easy to change.

 

[Robert]

Just to expand on what everyone else said, you do have four, but I found minve very easy to change. It took me about 45 minutes to change all four. My body lift did allow me to get my hands into spots that would have been more difficult without the lift, but I don't think they would still be all that bad without the lift. If your mileage is close to stock or at least where it has been running for the last couple of years (assuming it is at least 15 city, 19 highway) and you don't have any running problems or codes then don't change them untl you see signs. At about $60 apiece, it will cost you $240 plus your labor to change them when you can very easily get another 30K-40K miles out of them. I got my first O2 sensor code at about 90K so at that mileage I went ahead and did all four of mine. My Explorer died on me twice while cruising along. The second time it happened, I scanned for codes and pulled an O2 fault in my pending codes. That was when I decided to go ahead and replace them. My mileage was still better than new and besides the two occurances, there was nothing out of the ordinary. Had I changed my sensors two years earlier for $240, it would have been a waste of money and time. Some people say to change them at 60K miles, however the automotive shops (Autozone, Checkers and Pep Boys) say to change them at about 90K-100K. If you don't have any driveability issues or bad mileage, then you would see no benefit from changing them now.

 

[fvumbaca]

my gas mileage is at about an average of 17mpg, so i dont see an issue there..the only reason i was going to change them because of some of suggestions poeple have gave of changing them around 70k, but also after realizing its going to cost me about $240 i decided to wait but i'm going to take a look at them and see how bad it could possible be to change them later on if i have too. Thanks of the suggestions!