I have an 08 rangerXLT 4.0l with 144k and auto trans 4wd,when ordering OEM oxy sensors, DENSO or Bosch, are they marked for certain positions, my manual shows 4, 2 up, 2 dwn, trying to stick with motorcraft,....factory manual of that year gives 9f472-BA for upstream and 9g444-A for downstream, how do I know which goes where?
the only reason I'm sticking with oem is that they give the part #'s, I've heard Denso is also a good brand, kicking no codes, but crappy mileage 12mpg town like,also have heard they s/b changed out at 100k + any input obliged.
. I've looked hard in these forums to no avail about identifying them for bank 1 or 2, does it matter so much left or right, bank 1 ..pass side, bank 2 driv side...yes? Thanks ahead.SM

 

The only thing different on the upstream O2's will be the length of the wiring harness for each. As far as how to tell, whatever you take out of a position, whether lower or upper put one just like it back in. Once out you will see the difference. Be advised, these O2's have been subjected to intense for over 140 thousand miles, more than likely they are going to be REALLY tough to remove. I would take some penetrating fluid and give the threads a good dose and give it a little bit to work. Some of these O2's are in tight places and will test your patience. They make a O2 sensor removal tool if you are so inclined.

I replaced my O2's a year or so ago and used Bosch. Not a minutes trouble with them since. However, my truck is a 99 4.0 OHV engine which is vastly different than your 08 engine.

Good luck

 

Thanks for tip,yes very hard to get out,having tranny replaced,thought while that was out of the way, it looks like alot more room..albeit just as tight,I'll let my shop worry about R&Ring the 4, thanks again H.O.🙂
I was orig going to do job, but thought it s/b done while A/T out of the way, and though I do see Bosch o2s, they don't come in a set of upper and lowers and I see there are more than 1 type,so the Denso brand makes a set already direct replacement....again thankyou VERY much.

 

Heat up the bungholes with a torch. They come right out.

 

Thanks Tim, I'll mention to shop doing the trans. install, figured I'd have new sensors put in while tranny out of way, thanks again!