'89 Dies at Low RPM
Thread Starter
Junior Member
Joined: Apr 2017
Posts: 43
Likes: 1
From: North Central Arizona
Year: 1996
Model: Grand Cherokee (ZJ)
Engine: 4.0
I've done a lot to my '89 Laredo since I got it last spring.
Changed all the fluids, brakes, U-joints by front wheels were shot so replaced, and stabilizer bushings and links ( got rid of the squeaks and clunks ).
One thing that still bugs me though, is that the engine dies once in a while while backing up, and once in a while when coming to a stop.
I notice the rpm's drop below normal idle when that happens.
I put it in neutral ( 4 speed auto ) and crank it and it starts right back up.
I took it into a shop, asking them to check out the random dying, and also the blower fan wasn't putting out very much air, no matter what the fan setting.
They called me back the next day, saying they found a vacuum line disconnected, and both the HVAC fan and dying problem was now fixed. Bill was $117.
The blower fan now puts out a lot of air, but the random engine dying was not fixed. They suggested a full tune up, and wanted $400 for it.
I took it home and replaced plugs, plug wires, rotor and cap myself for about $60. One of the things I meant to do soon anyway.
This XJ runs great with a little throttle, drove it 1200 miles from Montana to Arizona last week moving down here, and got good mileage, although it was a bit slow on hills, lacking power when loaded down with camping gear, etc.
I did have a problem in Northern Nevada when the pulley on the alternator started chirping, then seized up, and I had to replace the alternator. To be fair, that could have been the original alternator, so at 28 years old, it lasted a good while.
What else should I check into ? Clean throttle body ? IAC ?
A mechanic friend suggested maybe check the ground from engine to frame, for the dying while backing.
I'm open to suggestions.
Changed all the fluids, brakes, U-joints by front wheels were shot so replaced, and stabilizer bushings and links ( got rid of the squeaks and clunks ).
One thing that still bugs me though, is that the engine dies once in a while while backing up, and once in a while when coming to a stop.
I notice the rpm's drop below normal idle when that happens.
I put it in neutral ( 4 speed auto ) and crank it and it starts right back up.
I took it into a shop, asking them to check out the random dying, and also the blower fan wasn't putting out very much air, no matter what the fan setting.
They called me back the next day, saying they found a vacuum line disconnected, and both the HVAC fan and dying problem was now fixed. Bill was $117.
The blower fan now puts out a lot of air, but the random engine dying was not fixed. They suggested a full tune up, and wanted $400 for it.
I took it home and replaced plugs, plug wires, rotor and cap myself for about $60. One of the things I meant to do soon anyway.
This XJ runs great with a little throttle, drove it 1200 miles from Montana to Arizona last week moving down here, and got good mileage, although it was a bit slow on hills, lacking power when loaded down with camping gear, etc.
I did have a problem in Northern Nevada when the pulley on the alternator started chirping, then seized up, and I had to replace the alternator. To be fair, that could have been the original alternator, so at 28 years old, it lasted a good while.
What else should I check into ? Clean throttle body ? IAC ?
A mechanic friend suggested maybe check the ground from engine to frame, for the dying while backing.
I'm open to suggestions.
CF Veteran
Joined: Apr 2013
Posts: 1,153
Likes: 7
From: Rowlett, Texas
Year: 1988
Model: Cherokee
Engine: 4.0 Inline 6
Well im pretty sure your model is still from the RENIX era, you should give cruiser54 tips a try. especially anyone of the tips that talk about refreshing grounds, it is a big help for renix models ... though i cant point you in the right direction, because of your transmission. Im riding with a manual.
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
I've done a lot to my '89 Laredo since I got it last spring.
Changed all the fluids, brakes, U-joints by front wheels were shot so replaced, and stabilizer bushings and links ( got rid of the squeaks and clunks ).
One thing that still bugs me though, is that the engine dies once in a while while backing up, and once in a while when coming to a stop.
I notice the rpm's drop below normal idle when that happens.
I put it in neutral ( 4 speed auto ) and crank it and it starts right back up.
I took it into a shop, asking them to check out the random dying, and also the blower fan wasn't putting out very much air, no matter what the fan setting.
They called me back the next day, saying they found a vacuum line disconnected, and both the HVAC fan and dying problem was now fixed. Bill was $117.
The blower fan now puts out a lot of air, but the random engine dying was not fixed. They suggested a full tune up, and wanted $400 for it.
I took it home and replaced plugs, plug wires, rotor and cap myself for about $60. One of the things I meant to do soon anyway.
This XJ runs great with a little throttle, drove it 1200 miles from Montana to Arizona last week moving down here, and got good mileage, although it was a bit slow on hills, lacking power when loaded down with camping gear, etc.
I did have a problem in Northern Nevada when the pulley on the alternator started chirping, then seized up, and I had to replace the alternator. To be fair, that could have been the original alternator, so at 28 years old, it lasted a good while.
What else should I check into ? Clean throttle body ? IAC ?
A mechanic friend suggested maybe check the ground from engine to frame, for the dying while backing.
I'm open to suggestions.
Changed all the fluids, brakes, U-joints by front wheels were shot so replaced, and stabilizer bushings and links ( got rid of the squeaks and clunks ).
One thing that still bugs me though, is that the engine dies once in a while while backing up, and once in a while when coming to a stop.
I notice the rpm's drop below normal idle when that happens.
I put it in neutral ( 4 speed auto ) and crank it and it starts right back up.
I took it into a shop, asking them to check out the random dying, and also the blower fan wasn't putting out very much air, no matter what the fan setting.
They called me back the next day, saying they found a vacuum line disconnected, and both the HVAC fan and dying problem was now fixed. Bill was $117.
The blower fan now puts out a lot of air, but the random engine dying was not fixed. They suggested a full tune up, and wanted $400 for it.
I took it home and replaced plugs, plug wires, rotor and cap myself for about $60. One of the things I meant to do soon anyway.
This XJ runs great with a little throttle, drove it 1200 miles from Montana to Arizona last week moving down here, and got good mileage, although it was a bit slow on hills, lacking power when loaded down with camping gear, etc.
I did have a problem in Northern Nevada when the pulley on the alternator started chirping, then seized up, and I had to replace the alternator. To be fair, that could have been the original alternator, so at 28 years old, it lasted a good while.
What else should I check into ? Clean throttle body ? IAC ?
A mechanic friend suggested maybe check the ground from engine to frame, for the dying while backing.
I'm open to suggestions.
Welcome to Arizona. What town are you in?
Go to my website www.cruiser54.com and do Tips 1,3,4 and 5 before throwing any other parts at it.
Thread Starter
Junior Member
Joined: Apr 2017
Posts: 43
Likes: 1
From: North Central Arizona
Year: 1996
Model: Grand Cherokee (ZJ)
Engine: 4.0
I'll go over the tips again, Cruiser.
I'm in Camp Verde, out 10 miles downriver by Beasley Flats, and don't have internet out there yet, so it took me a while to get back to this thread.
I'm in Camp Verde, out 10 miles downriver by Beasley Flats, and don't have internet out there yet, so it took me a while to get back to this thread.
CF Veteran


Joined: Nov 2017
Posts: 2,478
Likes: 275
From: Southern Texas (former AZ & Aus)
Year: 1999
Model: Cherokee(XJ)
Engine: I6 4.0L
Not sure if your 89 would have the same type as my 99 does... but what about the TPS? IF it happens when you're trying to take off and pressing down on the accelerator pedal, it might be worth checking into. Fairly cheap and super easy to swap out.
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::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
different fuel injection system.



