I'm troubleshooting poor gas mileage & rough idle. I'm thinking of changing the O2 sensors. No CEL lights, codes or anything else. I've had a cople people recommend trying it. How hard is it to change them (pre-cat). I can see both and reach one, but can't find where the wiring goes on oone and can barely touch the end of the other (driver side)

Let me be more specific. Is there a trick to changing them? Looks like the passenger side would be easier accessed through the wheel well. Or if anyone would have a better suggestion to try first, I'm open, especially changing both sensors is $100 I'd rather not have to spend unless necessary.

 

Before thowing money at it I'd get a good OBD scan guage. That will let you see how quickly the 02s swing from high to low and back again. Compair your ranger to a newer car and you'll see what I mean.

As 02s get high milage on them the volts swing slower and slower until it finally gets bad enough to throw a CEL.

Who knows.. if it's not your 02s you will now have a good scanguage paid for. And it'll help aid in trouble shooting any OBD2 car/truck in the future. (1996+ years)

IMO it's money well spent.
www.scanguage.com
www.autotap.com
http://www.actron.com/product_category.php?id=249

Rich

 

would a 2000 be ODB I or ODB II? Would that matter when buying a scan gauge?

 

1996 and later cars are all "OBD2"

Rich