XJ.89.Limited

What's the recommended o2 sensor for the renix? And where is the cheapest place to get it? I think mine is either shot or soon to be shot. My mpg tanked to about 10 from 13. I'm gonna run this tank of gas and then fill it up again and see if it was just bad gas. My last fill up was 12.7 with a little heavier of a foot and cold temps out. I averaged 13-14 in the summer and fall. Sometimes 15 if I was lucky.

OnTheOffRoad

You may want to check other things before jumping on the O2 sensor.

Many items can tank your mileage per tank in addition to driving conditions
Plugs,wires, cap/rotor,injectors dirty, poor airflow (in or out)

Check here for how to test some sensors under your hood:
http://www.lunghd.com/Tech_Articles/...iagnostics.htm

I just did an O2 sensor (as insurance going into a failed smog test in CA), about $75 at a local parts store (Bosch I think, did a BMW as well which I'm sure was Bosch).

CCKen

NTK 23553

XJ.89.Limited

I did a full tune up not too long go, so I know all that is fine. Probably should've stated that too, haha. I'm gonna check my air filter to see how that looks and pull a plug or two to see how it's burning. I searched all over and the the o2 sensor can't really be tested to see if it's functioning properly, just functioning in general. I had a thread on here a while ago when it was acting up before. It goes through phases, typical renix.

I have an aftermarket muffler which helped me pick up another mpg or two back in the summer. I'm getting a tailpipe bent up soon to give it a little back pressure and keep the noise down (loud as hell side exit). I think my cat could be a culprit in the bad mpg but I'm not looking to replace that any time soon. That'll be a fun job to do after all the years of salt and rust on the flanges.

I could run an injector cleaner through it, but I don't want to loosen up 23 years of gunk in the lines and clog stuff. I'm afraid somethin will get messed up. Then I'm out of a DD.

XJ.89.Limited

You sure this is for the renix, not the HO?

CCKen

Right off the NTK site for a 1989 Jeep Cherokee 4.0.

If this is not your Jeep, give it a try here:

http://www.ngksparkplugs.com/part_fi...t.asp?mode=nml

XJ.89.Limited

That looks like what I need. I saw a Bosch one that said "direct fit" for $50. I know there was a big debate somewhere whether to use Bosch or NTK for the renix vs. HO motors a while back. I wasn't sure which one to use. It looks like it would be fine since it has the 3 prong plug on it.

cruiser54

Go NTK.

And don't sweat it about using an injector cleaner.

XJ.89.Limited

Thankyou cruiser, I was hoping you would chime in on this. I just wanted to get one or two opinions on either brand to clear things up.

On another note, what brand injector cleaner does everybody recommend? That's usually cheap, I can pick up a bottle next time I get gas. It just sucks that most of my paycheck goes to gas cuz I drive a ton. Yay college!

CCKen

I don't know about everyone, but I suggest Techron. It's readily available at the auto parts stores.

BG44K is also good but hard to find and expensive.

The Rooster

I also you techron ever so often my jeep gets in the 20's for mpg I can't complain to much

robinz

I went with a Walker in my 1990XJ and has worked out well. I made a video that may help you get prepared when it comes time to do yours.

XJ.89.Limited

Rooster, I can't believe that mpg. I think my sister's subaru gets that with a motor half the size, haha.

CCKen, I'll see if I can find some techron by me. I'll run a bottle through my tank and see if it helps any.

robinz, I'm gonna watch that video right now. Thanks!