ugeely

Got a 98 Cherokee 6 cyl that's developed a new problem. It'll run fine for a few days then out of nowhere the chk engine light comes on and it'll sound like its either getting too much or too little gas...sounds like its running on 2 cyl. Also get a bad odor. After revving it for awhile it'll run fine for a few days...then bam..back again. I tried dry gas hoping that would do it but no go. New cap, rotor and plugs. After it straightens out the light goes out till the next bout. Baffles me how it comes and goes. Thinking it may be a fuel pump, but thats alot of money if for nothing. Any ideas out there ? I want to add that after cap and rotor replacement i took it out ..ran fine..stopped and floored it up to 50..ran like a beast.."but"immediately when i slowed and kept it at 40 or so it started right in with the skipping, barely made it home a mile away where it died. Started it again immediately and it idled great...rev's great. But light still on.

CCKen

You'll have to try and get the Diagnostic Trouble Code(s). They may be "Pending" so use a scanner/code reading that can pull pending codes.

Klutch

First thing I would suggest is having the battery and the charging system tested. Most chain parts store will test them for free.


I had a 98 XJ with those symptoms and, strangely, it turned out to be a bad battery. Replaced the battery and all the problems went away.

ugeely

Know what Klutch...you may have hit the nail on the head. I'd of never thought that ..but for the last 3 weeks battery's been dying and had to charge it a couple times. Weather here in upstate NY been below zero for a month. I figured it was just that draining battery. I will be checking this out...thanks

Klutch

Yep, sure sounds like you have a battery problem. Based on my experience, the Jeep computers don't like a bad battery. When the battery starts to go, the computer gets pissed!

ugeely

New Battery installed,started up, chk eng lite out, drove a mile and did it again. Feathered it home and died in drive. Started right back up and idled perfect. Next try fuel filter i guess.

kdot

I'm not extremely familiar yet with the 4.0, but I believe there is a port to test fuel pressure. Test fuel pressure on start up and under load. You could have a faulty pump?

Is it backfiring? Or just missing?

Klutch

During research for my Cherokee's problems, I've seen multiple cases where the crank position sensor was failing and would stop working when it got hot. So, you might test the crank position sensor.

Sounds like you had a bad battery as well.

ugeely

It's not backfiring, just very little spits now and then ...like loading up when it's running good. When the problem starts and i'm feathering it to get home it has a hissing spitting sound in engine compartment..like spitting back thru a carb (that it doesn't have), like it's missing on all but a few cylinders. It really acts like i have half gas and half water in the tank...best way to describe it. I did the gas treatment and put fresh gas in, just wondering if i may of gotten a tank of real bad fuel and there's still water in it. How do you have the crank sensor tested ? This all started when the tank was real low and i filled it up. I have 3 vehicles and this one only gets driven when the roads are bad and,(my bad), i neglected to keep the tank above half.