CA-XJ

Ok guys I've been searching long enough and come up on nothing but dead ends. 1991 Jeep Cherokee, 4.0l, AW4 Transmission, NP242 J Transfercase. I was driving home from the off road expo a couple weekends ago, and when I went through a freeway interchange, my Jeep just sporadically lost power. My RPMs dropped and started slowing down to like 25 on the freeway, then sorta surged a little, then picked back up. Kinda felt like running out if gas, but I know there is no way I went through my tank already. The only thing that I can think of so far is maybe my catalytic converter (California) had clogged for that amount of time, then cleared out again. I already have a new cat to replace it with, along with a new muffler. I know the cat is bad because the internals are broken down and rattling. So any suggestions as to what could make this sudden drop in power? Thanks all.

RTorrez1

Check out you CPS. When mine was going out it would do the exact same thing.

CA-XJ

Is it something i can test, or something that should just be replaced?

RTorrez1

You can test them but the test isn't always 100% accurate. When my CPS was going bad it tested good. I went ahead and changed it out and I had no more problems. BTW, You can do a search on here and there are a couple of write ups on how to test it. Also if you do replace it. Do yourself a big favor and replace it with an OEM one from the dealer. The aftermarket one tend to have a very short lifespan. That is if they work at all, They do have the tendency to be bad right out of the box.
EDIT...
I found it for you. Go to Cruiser's post and it the 7th post down.
https://www.cherokeeforum.com/f51/cr...x-tips-153657/

CA-XJ

Is there a difference between Renix CPS and H.O. CPS? Forgot to mention i have the H.O. motor.

RTorrez1

It's the same procedure for testing the CPS.

CA-XJ

Ok thanks, will definitely give it a shot.

freegdr

Did any codes show up when you checked them ?

CA-XJ

I've got OBD1 and don't have the list of codes to refer to.

Bustedback

Google is your friend, you'll find the codes listed. It sounds like the fuel pump is crapping out on you. The catalytic converter will not clog up and then magically unclog.

CA-XJ

Yeah the fuel pump could be another option because my gas gauge has been about a 1/4 off since i bought my XJ.