Help. 1998 Jeep Grand Cheroke 4.0

[MTT]

Looking for some suggestions / help

My mom has a Jeep Grand Cherokee 4.0
It is in really nice shape. , but

over the past 6 months it has had progressively worse issues where it stops running.
At first it would just cut off shortly after starting. Now it frequently will cut out for a few seconds while cruising down the highway @ 70MPH

There is never a check engine light. Mechanics see nothing wrong when they look at the computer.

It is getting progressively more frequent.

Yesterday I had the Gas tank dropped, cleaned, fuel pump/ filter replaced. fucker cut out again going up the road in our hood.

HELP! what is it!!!!

Money no object!

[El Chupacabra]

Money no object = buy something more reliable than a 1998 ZJ.



That aside...

Crank position sensor and throttle position sensor will cause similar cutouts, but usually throw a code.

Battery strong? Weak batteries can do weird stuff.

All ground straps good?

Coil failure? Does it start right up again? Idle OK?

[MTT]

Money no object = buy something more reliable than a 1998 ZJ.



That aside...

Crank position sensor and throttle position sensor will cause similar cutouts, but usually throw a code.

Battery strong? Weak batteries can do weird stuff.

All ground straps good?

Coil failure? Does it start right up again? Idle OK?

crank sensor replaced. along with a few others.

always starts right up. - but sometimes when you put it into gear to go, dies. But then start right back up.

[stuckathuntermtn]

uhhhhh, spark plugs?
Or literally anything other than a Chrysler.

[hawkgt]

did you put in new gas or re-use old?

first reading I thought water in gas line, crank sensor, or fuel pump. any vacuum lines?

[El Chupacabra]

crank sensor replaced. along with a few others.

always starts right up. - but sometimes when you put it into gear to go, dies. But then start right back up.

What about my other questions? Electrical etc. Things that are not related to sensors generally do not throw codes.

Another one - that transmission should be a 42RE - neutral safety switch in transmission? When those start to fail in the AW4 transmission Jeep used in the XJ, they generally won't allow the car to start - haven't seen it before where they kill the motor while running, but may be possible. NSS failures do not throw codes.

[MTT]

What about my other questions? Electrical etc. Things that are not related to sensors generally do not throw codes.

Another one - that transmission should be a 42RE - neutral safety switch in transmission? When those start to fail in the AW4 transmission Jeep used in the XJ, they generally won't allow the car to start - haven't seen it before where they kill the motor while running, but may be possible. NSS failures do not throw codes.

that's interesting, transmission was replaced 3 years ago. I never thought there was a transmission problem, thought it was a sensor pressure problem.

when you start looking there is SO MUCH electronic shit on these things!!!

and then when you look what it has and what it is capable of, it would cost 60,000$? to replace it, and really you cannot replace a solid front and rear axle select trac Jeep.

[Rideski]

Why would you have a grand with a 4.0?
How many miles on the engine?
Drop a new engine in and get a v8

[MTT]

Why would you have a grand with a 4.0?
How many miles on the engine?
Drop a new engine in and get a v8

ahh, you have much to learn. the 4.0 strait 6 is a bomb prof engine that will go FOREVER. and is perfect in shitty traction conditions

[Rideski]

I own one bub. It’s fine in the Cherokee but underpowered in the grand.

[TeleTahoe]

Look into the PCM. I have a 95 4.0 that was doing this a few years ago.
To get a new one you have to get in programmed for your vin. Which means it’s expensive.

I opened mine up and solder new capacitors.


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[MTT]

I guess I need to find a complete schematic and just go through the thing and disconnect / clean reconnect every wire in the dam thing.

It's just frustrating that no mechanic at any price can fix it!!!
All the tune/ sensor replace. ect ect has been done and it just keeps getting worse.

It would almost be better if the pig just quit running and we flat bedded it into a garage and they fixed it.
It's just an annoyance.. And money has been thrown at the big ticket stuff

to make it worse it looks like its a couple years old. She has babied it for 15 years;

Mom is 76 on SSN does not need a car payment. Nor do I.

[skimaxpower]

Money no object = buy something more reliable than a 1998 ZJ.

Or literally anything other than a Chrysler.

Trying to make a Chrysler product reliable is a fool's errnad. Stop falling for the sunk cost fallacy. Dump this lunker and get a more reliable vehicle.

[splat]

I own one bub. It’s fine in the Cherokee but underpowered in the grand.

I've had about eight or ten jeeps. The 4.0 is bullshit, especially in the grand. I have one that's a '98 now. Just replaced the engine at 269K. Replaced the computer at 220K for issues like this. Had another 4.0 that did the die at any moment thing starting at 80K. The stealership kept saying they fixed it but didn't, so I waited for a weekend when the shop peeps were gone and traded it in so it could be their problem. The 4.0 is indeed underpowered in the grand cherokee and only gets a mile or two more mpg than a 5.2.

I drove my last 5.2 into the junkyard at 400K. Got the best value out of it than any car I've ever owned. I also had a manual 5 speed 4 cyl Cherokee in 1990 that was tied for first place in my Jeep memories. The 4.0 has no notable qualities that would surpass the performance of the 4 and 8 cylinder jeeps I've had.

Best advice - go talk to the guys at Folbecks. They know jeeps better than anyone in Reno. There's also some other guys further east on glendale that do killer diagnostics.

[MTT]

I've had about eight or ten jeeps. The 4.0 is bullshit. I have one that's a '98 now. Just replaced the engine at 269K. Replaced the computer at 220K for issues like this. Had another 4.0 that did the die at any moment thing starting at 80K. The stealership kept saying they fixed it but didn't, so I waited for a weekend when the shop peeps were gone and traded it in so it could be their problem. The 4.0 is indeed underpowered in the grand cherokee and only gets a mile or two more mpg than a 5.2.

I drove my last 5.2 into the junkyard at 400K. Got the best value out of it than any car I've ever owned. I also had a manual 5 speed 4 cyl Cherokee in 1990 that was tied for first place in my Jeep memories. The 4.0 has no notable qualities that would surpass the performance of the 4 and 8 cylinder jeeps I've had.

Best advice - go talk to the guys at Folbecks. They know jeeps better than anyone in Reno. There's also some other guys further east on glendale that do killer diagnostics.

So you are recommending Folbecks? I am open for suggestions , it's got to be some stupid little thing, that no one can pin down !!

[Rideski]

@Splat Eh, I got 215,000 out of my 4.0. It was a great storm chaser and lots of forest road camping/hiking access. Also great for parallel parking downtown. They get a lot of hate but worked well for me. It's retired to grocery getter now unless I make a toy out of it, but prolly just let it go.

@MTT you never said how many miles it has, and Chup asked about the battery.

[splat]

So you are recommending Folbecks? I am open for suggestions , it's got to be some stupid little thing, that no one can pin down !!

Uhhh, YES, I AM!!! This electrical glitch shit is not uncommon in Jeeps. I've seen Folbecks diagnose issues nobody else could. If anyone can say "yeah, it such and such," and be right, it's them. I'm gonna say new computer. They run around $300-$400 online.

[mcski]

MTT - i had a somewhat similar jeep issue w cutting out. iirc Thermostat replacement was the fix. Wasn't too expensive as I recall

[MTT]

Uhhh, YES, I AM!!! This electrical glitch shit is not uncommon in Jeeps. I've seen Folbecks diagnose issues nobody else could. If anyone can say "yeah, it such and such," and be right, it's them. I'm gonna say new computer. They run around $300-$400 online.

the new upgraded computer might be the way to go.
500$ bucks would e an easy dump to make it right

FYI 218,000 miles

[skaredshtles]

[XXX-er]

I.

It would almost be better if the pig just quit running and we flat bedded it into a garage and they fixed it.
It's just an annoyance.. .

yup IME intermittent bugs can be a bitch cuz all you can do is repalce one thing after another until its fixed

its 20 yrs old ...get rid of it

[El Chupacabra]

It’s fine in the Cherokee but underpowered in the grand.

X2 on this, also from my own experience in owning a bunch of XJs, one WJ, and one LJ, all with the 4.0. The 4.0L was great in its time, reliable, easy to work on when needed, and all the problem spots are well-known by now. Downside is that its time was 1987-1995 IMHO, and in the past 20 years, engines have come a long way.

I would not pick a 5.2 or 5.9 ZJ, but that is solely because I think Chrysler transmissions are a pile of shit. The only ZJ I'd suggest buying is the early '93 model with the AW4 transmission.

MTT - at 200K+ miles on a Jeep that is over 20 years old, it's time to ditch it. Unless your mom likes random side-of-the-road breakdowns. This is a vehicle for Jeep enthusiasts or teenage kids.

[PNWbrit]

really you cannot replace a solid front and rear axle

Why does your Mom need solid axles?

[bmg97]

Are you using mopar replacement sensors ? I would only recommend using factory replacement for electronics. I went through like 4 TPS sensors from autozone and they all sucked. 1 from mopar did the job.

ECM ?

https://www.cnet.com/forums/discussi...oblems-311804/

[tuco]

Ignition switch
You're welcome