BigzXJ

This post my be more of a help for me to vent then anything. I have about had it with my 90 cherokee. I have been spending 6 months to solve this problem and today I felt like putting TNT into the tail pipe and lighting the fuse.

The problem she acts like its running out of gas or like its missing at highway speeds (which is the most common time it does it). It will also do it when i accelerate from stop sign. I have figured out it does it when I run in between 1800-2200 RPM's. When running 65 i am usually at 2000 rpms and it jerks like its running out of gas. I can let off it stops, give it gas, it stops. It runs well except for this problem. I can put the pedal to the floor and I can smoke the rear tires. I just don't understand.

Today was the last strew. I put a brand new TPS and it did not change a thing. I have saved three weeks for a 40 sensor and changed NOTHING.

What I have done for the last 6 months which none have helped or can the problem: CAP, ROTOR, WIRES, AND PLUGS. USED DISTRIBUTOR, FUEL PUMP, FUEL PUMP REGULATOR,(FUEL PRESSURE GOOD), ECU, CRANK POSITIONING SENSOR, AIR FILTER, FUEL FILTER, ALL INJECTORS WORK AND DO NOT LEAK. I have also swapped parts off of a friends cherokee and nothing like the MAP sensor.

I don't know what else to do I am tired of checking sensor and replacing them and nothing seems to work!! Anyways, thanks everyone you have already helped me get this off my chest. Sorry its so long.

1990 Cherokee 4.0 4X4 276,000, 95 H.O. engine 66,000 under the hood, AW4 tranny

The Rooster

I actually have the same problem it is really werid it comes and goes.... it seems to have gone away since it has gotten colder...

BigzXJ

Found out my car pool buddy got a new job, so now I will have to start driving my 90 again daily. I have to figure this problem out fast and CHEAP. (single family income of 4) Taking it to a shop is out of the question. I did forget to mention in the first post that I have cleaned the throttle body, and changed out the IAC with a used one and it did not change anything. I have crawled all over it and checked for anywhere rubbing on anything and all looks good. Any ideas would be great thanks.

bigvig

You putting bad gas in it? There is a local pump that I prefer to do business with, but every time I do, my 99 does that exact same crap. And its usually before a long highway trip, so I get on the highway and hit 78mph and it will sputter, jerk and hesitate off and on until I run through that tank.

On a side not, have you ever Seafoamed anything? Try doing a triple treatment and see what happens. Yeah, its another $25 bucks, but it might do the trick.

If its not throwing a CEL or any codes, technically nothing is wrong. She might just be getting old and wearing out.

98sportjeep

x2 on the bad gas!!!! mine was bogging and stuttering at idle, and at low speed and high speeds.. Checked the FP at the rail and the gas stunk!!! I had a half a tank in their.. I hadded 6 gallons of 93, Dry Gas( takes water out of the fuel and gas lines) and a complete fuel additive... Let it sit over night and it hasnt happend yet. except for one time idling in the driveway.... Knock on wood.. but you should check your fuel!! if you have a steel tank, you ma want to drop it and check for rust and etc!!!

James P

Bigz I have seafoamed the heck outta mine every fill up. Where are you Getting gas at? QT as u know has ethanol , over time u will get water in the tank using it. If u haven't seafoamed or some other fuel drier. Try it and see what happens.

BigzXJ

Keep in mind this problem has been on going for six months. I have used differnet additives such as seafoam. Have used non-ethanol, with ethanol, different octane, and several different stations. Have dropped the tank and cleaned it out. Fuel pressure is where it should be, have also driven with the fuel gauge hanging out of the hood to see what it does and its fine.

The Rooster

I have also tried different gas gases.... different octane used dry gas.. my fuel pressure is also good...it even did it on a full tank of gas... it doesn't smell bad... but it usually does it on the highway also... i am looking for any suggestion... this is also my daily driver.... and it just comes and goes.... its werid... when it started i did a complete tune up etc... cleaned all the injectors... i have yet to drop the tank... kinda do not want to do that yet...

BigzXJ

It's a 90, few years before the OBDI codes. Wish it did so it would point me in the right direction. And its a good little cherokee, body and interior are showing its age, but mechanically its sound. I have had it for 5 years, dropped a engine it, and this is the first real big issue with it since then.

That's how it started out, every now and then. Now ALWAYS does it around 65 mph. I makes you wonder if its going to make it to where you are going. I have read several threads with this problem and most have had answers on what fixed it but everything I have tried changes nothing.

The Rooster

yea merging onto the highway and when it hits around 65mph is when it most of the time it happens... If it happens... it didn't do it today tho... now this is funny we have the same problem and live no where near each other... So i do not think it is the gas... how many miles on yours? I have 143k... as for mine showing age its not... it has been crazy mainted...oil changes anything that breaks has been repaired... I do need tires but i know thats not it lol...

BigzXJ

1990 Cherokee 4.0 4X4 276,000, 95 H.O. engine 66,000 under the hood. I bought it with a blowen engine, and PO said the tranny was rebuilt 5 months before the engine blew.

The other threads I have read with our same problem: one guy had a 95 and ECU fixed his. I tried it and Failed. Another guy had a 92 and TPS fixed his. I tried it and Failed.

The Rooster

yea mine is a 143k all org Renix... this is the 1st problem really for me 2... so far... so you have a HO not a Renix then...

BigzXJ

H.O. engine block only. Every thing telling it to run is all the renix brain and sensors.

Turbo X_J

Couple of things:
1. If it's a 1990 it's OBD1 and can store codes.
2. First place to start is with a compression test. There is no reason to progress to fuel and ignition if the engine is suspect.
3. Kind of a moot point but why didn't you harvest all the 1995 fuel and emissions jazz with the motor?

BigzXJ

From what I understand 90 was the last year of the renix, and thought they did not store codes. Also I have a scanner port under the hood but, from everything I have read the scanner is rare to find and only this scanner will work.

I can try to do a compression check, it just acts like something fuel or ignition related. Runs good but around a steady 2000 rpms just acts up. You can floor the pedal and it takes off like a rocket no problems. I would think something internal in the engine would be worse at higher rpms.

At the time of the engine swap I knew nothing about the XJ. After 5years of owner it I have learned its a beast all in its self. And knowing what I know now I would have had to pull the PCM and the wiring for it to work right, right?

If I am wrong please let me know, I won't to understand my cherokee more. Thanks for everyones help.