Blue94xj

I have a 94 Cherokee se. When i drive it and get up into overdrive it's wants to buck and jerk when I barely accelerate. Also it starts to pop through the intake and occasionally out the exhaust. New parts replaced in the last month.

Gas tank and fuel pump
Water pump
Thermostat
Fuel filter
Tps (throttle position sensor)
Idle air control valve
Air filter with K&N
Stock Muffler and gutted the cat due to it rattling
Power steering pump

I need help been chasing this problem since I've gotten the jeep. Anybody had this probes and found the fix?

Jooman07

First off, is the CEL on? And if so, have you had the codes ran? Not sure but I think I've heard of a bad CPS causing similar issues.

SeriousOffroad

Check and tighten the bellhousing to engine block bolts, all of them.

Had this problem on my son's old rig. The bolts were loose and the engine would shift throwing off the Crank Sensor/flexplate alignment. Ran smooth as a babies butt once we tightened everything up.

Sounds farfetched, but it's worth a look.

madmanmarty

I have got to check these ^^^.

Crash_Course

I had a bucking issue when I got mine; between 40-55 mph at steady throttle it would start until I either gave it gas or let off. Replaced the clapped-out shocks and it went away.

iluvmud

I'm starting to see this in my 99, just all of the sudden I'll start accelerating and i feel it jerk a bit and i hear the exhaust pop a little...... happening more and more now. I haven't done anything to it yet, was hoping it's a common problem that i wont have to kill myself trying to find the cause.

iluvmud

no one huh?

Jooman07

Well since the OP hasn't responded with whether or not any of the suggestions fixed the issue we don't know. Did you try any of the suggestions since it sounds like a similar issue?

*The Dude*

Just a question because I didn't see spark plugs on the list. Are they in good shape? Replaced recently as well?


Worn out plugs or wires will cause this issue.

Redneck99xj

Mine has been doing this too, replaced tcm, problem went away for a few trips and was back, just got a cel today for cam crank intermittent fault and I replaced the crank sensor which looked brand new with one off another xj and took if for a test drive and so far no bucking. We will see over the next few days however.

tech

I would check the plug wires cap and rotor and the coil could be getting weak .and like (DUDE) said your spark plugs .

Gryphon439

Bump. I'm having this issue myself. I had a CEL 27 that ended up being my #1 fuel injector was stuck open. I resolved that with brand new mopar OEM injectors (all 6). During the troubleshooting, I did a tune-up, changed the CPS (MOPAR Part), and Idle Air Control Valve (MOPAR Part). She was running like a top when I took her for a spin around the neighborhood, but when my wife and I drove down the freeway and back (About 25 miles round-trip, there was no issue.

We left the house and drove down the freeway at between 65 - 75 mph to get dinner at a local shop (Take-out only b/c COVID) about 12 miles away, shut the engine off while grabbing the food. We then went to a local park to eat, only a mile or two out of the way home and shut the engine off. We have a dog that was barking at the local dogs as they pass by so I ended up just idling the whole time in park so I could operate the windows (my battery had died not too long before I got her running again so I didn't want to abuse it). We then started on our way home. Had no issues driving through the city streets and down the freeway (about 5 miles in total) before the Jeep started bucking hard and popping off back-fires left and right. I calmly took account of my surroundings and all of the gauges, everything but my RPMs seemed to be in order and there was no visible smoke. Even still, she persisted to buck and pop for about a mile so I took the off-ramp and pulled over. Taking a look under the hood I could not see anything out of order, and checked all plug wires for a tight connection, including at the cap and that the cap was on tight. I then disconnected my coil and re-connected it as I know that these can be a problem at times. Fired up and ran great for about 2-3 miles, then the bucking came back.

It seemed that the only way I could calm the poor lass was to shift into neutral and let off the throttle, 50% of the time she would pop and stall , the other 50% she would pop and level out. With that, I was able to limp her home and into the driveway. She is idling just fine in the driveway and never stutters or stalls, she only does so on the road under load. I tried, by doing a bit of throttle while she's got the parking brake applied and that doesn't seem to affect her either. Only way I have been able to repeat this is driving down the street applying throttle.

Two things I am thinking to be of suspect are:

1. Idle Air Control Valve: I know it's new, but if it is bad I believe it could be causing a stall and bucking
2. My O2 sensor could have gotten fried from the raw fuel that was passing by when my #1 cylinder injector was loading up with fuel

Any thoughts on either of these possibilities or other possibilities? I'm feeling lost...

Cordless telephone

I had the same problem for the past few months. Then I bypassed the Ballast resistor (ceramic thing on the driver side fender). Hasnt given me a problem since.

Gryphon439

Really!? That ballast resister could cause this?!? Should I replace it instead of bypassing it?

Gryphon439

I tested the ballast and found that it has 1.6 ohms resistance, and an amperage of 2.25a based on the calculation I found on this post: https://www.cherokeeforum.com/f2/fue...3/#post3589321

Finding that my ballast resistor was fine, I decided to swap out my Idle Air Control Valve since I wasn't sure if the new one was good, but knew for sure that the old one was working fine. That did not fix my situation either. My next step is the O2 sensor unless someone else knows something else I should try.

Still no CEL or codes.