Help! Oxygen O2 sensor help

[blade0015]

hey, so my check engine light is on and i got it scanned. It says both upstream O2 sensors have had it. Im up at college so its pretty hard to work on car so i took it to dealer and see what the estimate was. :fire: $500 bucks for just both sensors. Now I just got this car-1998 5.0 Moutaineer 2wd, so from searching ive found there are four 02 sensors. Where are they? and how hard are they to change? Any pictures or any info would help alot! Thanks alot
:roll:

 

[Turdle]

The sensors are about 50-75 bux each depending
There are 2 parts listed, and beleive it or not the expensive one has shorter wires, so get 2 of the less expensive
Theupstream o2 sensors will be the closest to the engine, downstream sensors are after the first cat. converters
The passenger side upstream o2 can be a pita to plug back in, unless you remove the center console, pull back trans hump carpet and remove the access panel on top of hump.
It sounds harder than it is, certainly not 350 worth of labor though.
First thing I would do is disconnect your battery for a few minutes to reset the computer. The code may not reappear.

Any shop should be able to replace both in 1 hr
Actually less but 1 hr labor charge would be fair

 

[blade0015]

so should i go to shop? or try on my own? Damn dude so hard to change?

 

[Turdle]

try resetting computer first
Then if that doesn't work
Wait for exaust to cool,then from underneath, passenger side, shine a flashlight up between pipes, toward transmission. Uo close to top of trans is where the hard plug is. ( both the upstream and downstream sensor's plugs are in this area, don't get them mixed up) If you can reach up and unplug it, then the hard part is halfway done. 7/8" wrench will loosen o2 sensor. now screw new one in, and reach way up , plug it in.
The driver side( Bank 2) o2 sensor is cake, all right there in front of you, and it is underneath, right in front of transmission.

 

[blade0015]

how i kno which is up stream and which is down stream when im lookin up there? should i go to Discount and just ask for the Upstreams? is there a difference?

 

[Turdle]

sensors upstream of the cats are called upstream, after the cats are called downstream. They are all the same "sensor". For replacing you'll have to follow the wire, from the sensor to the plug.

 

[mora0004]

free fix, almost

Try swapping the downstream O2 sensors with the upstream O2 sensors. The down stream sensors are not used for engine control, and they are in a less harse environment than the unstream sensors. Swapping the sensors will buy you at least a few mounths of time.
To remove the upstream O2 sensors remove the front tire and the plastic seperator between the wheel and the engine. You can also remove the sensor from underneath. The wires are hard to reach from underneath though.