xjcruiser1664

Hi my buddy has a 1988 jeep cherokee/ wagoneer with a 4.0 and he is having a server misfire we replaced plugs cap and wires put all new injectors in and tested the fuel pressure so far does anyone know what else could cause this

1990 XJ-Texas Edition

Crank position sensor.
Trust me, give it a while and Cruiser54 will probably be in here in a bit and tell you the same thing.
You got a DMM? Or or even an ohmmeter?

xjcruiser1664

Ye I have an ohmmeter and that what I was thinking it could be but wasn't sure.thanks I will check that tomorrow and let ya know what happen thanks for the help

cruiser54

Click on the "pink link" in my signature and start reading. Highest probabilities are in the first posts.

Also, describe to us your definition of "misfire".

xjcruiser1664

Really rough idle and rough when driving shakes everything also a mechanic told me it was a misfire

cruiser54

Do a compression test and post up the results.

RTorrez1

Have you tried to see if it has any stored codes? Also a bad CPS won't cause a misfire or a rough idle. A bad CPS will cause a no start of a sudden engine shut down.

terri lynn

good afternoon,
I don't have any idea were my fuel filter is on my 88 cherokee 4.0. :9 Can someone enlighten this ole' gal?
May I also ask, what is the first step to figuring out why my brakes won't hold pressure? (I know I should check for air in the brake lines-but-do not know how I achieve that all by myself).
Thank you ever so much for any advice you can give me.
Terri

terri lynn

I guess I should of let you know that I too, am having idle problems and have done some of your suggestions as far as cleaning the C101 valve and am going to walk to auto parts store to purchase some dielectric grease and brake cleaner to finish up the C101 valve.
Terri