"Help" Loss of engine power while driving
01-09-2019, 07:01 PM
#1
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Year: 1998
Model: Cherokee (XJ)
Engine: 4.0L inline 6
"Help" Loss of engine power while driving
My 1996 xj will lose engine power while driving, when I accelerate the rpm drops randomly if I lay the pedal down the problem is gone. I think it has something to do with fuel distribution but not sure what to go after first. It has the stock fuel Injectors installed. I've tried sea foam, fuel line anti freeze and higher octane fuel. Here's a link to a video of it happening. https://www.reddit.com/r/CherokeeXJ/comments/a82l3a/loss_of_power_when_driving_could_this_be_do_to_a/?utm_source=reddit-android
01-09-2019, 07:39 PM
#2
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If your 96 has OBD2 support, I would strongly recommend getting an inexpensive scanner such as the BAFX OBD2 scanner (amazon for around $20). In order to see what the fuel trims are doing. Stalling and hesitating when first depressing the accelerator is one of the key symptoms of a mixture problem, and having the proper response return when pedal is depressed all the way down is a key sign that the mixture is not right during normal operation, but improves when the computer goes into WOT mod (wide open throttle) which ignores what the oxygen sensors are saying about the mixture and operates off a pre-defined set of values.
Most commonly, this is caused by an upstream O2 sensor that is beginning (or already has) failed and is sending erroneous values to the computer. O2 sensors are usually only good for about 110k miles (to give an idea).
Secondarily, the MAP sensor can cause similar behavior if it is not measuring the incoming air correctly. Though the O2 sensor would be my first bet.
Most commonly, this is caused by an upstream O2 sensor that is beginning (or already has) failed and is sending erroneous values to the computer. O2 sensors are usually only good for about 110k miles (to give an idea).
Secondarily, the MAP sensor can cause similar behavior if it is not measuring the incoming air correctly. Though the O2 sensor would be my first bet.
01-10-2019, 09:41 AM
#3
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Year: 1992
Model: Cherokee (XJ)
Engine: 4.0
I'm having the exact same issue with my 92 XJ. Cannot for the life of me figure out what it is. All new spark plugs, new O2 sensor, vacuum lines are good to the MAP sensor, new TPS, relatively new fuel pump. No clue what is causing it but I'm experiencing the same as you. RPMs begin to drop and engine bogs down and makes a popping noise. Flooring it resolves the issue
Last edited by Tom Jackowski Jr.; 01-10-2019 at 09:54 AM.
01-10-2019, 11:32 AM
#4
CF Veteran
I'm having the exact same issue with my 92 XJ. Cannot for the life of me figure out what it is. All new spark plugs, new O2 sensor, vacuum lines are good to the MAP sensor, new TPS, relatively new fuel pump. No clue what is causing it but I'm experiencing the same as you. RPMs begin to drop and engine bogs down and makes a popping noise. Flooring it resolves the issue
01-10-2019, 06:39 PM
#5
CF Veteran
I'm having the exact same issue with my 92 XJ. Cannot for the life of me figure out what it is. All new spark plugs, new O2 sensor, vacuum lines are good to the MAP sensor, new TPS, relatively new fuel pump. No clue what is causing it but I'm experiencing the same as you. RPMs begin to drop and engine bogs down and makes a popping noise. Flooring it resolves the issue
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01-12-2019, 10:28 PM
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Year: 96
Model: Cherokee (XJ)
Engine: 4.0
My 1996 xj will lose engine power while driving, when I accelerate the rpm drops randomly if I lay the pedal down the problem is gone. I think it has something to do with fuel distribution but not sure what to go after first. It has the stock fuel Injectors installed. I've tried sea foam, fuel line anti freeze and higher octane fuel. Here's a link to a video of it happening. https://www.reddit.com/r/CherokeeXJ/...reddit-android
Felt like a giant miss, and thought I had it cured with a new ignition coil,,,but the issue returned,,,very random
One day I was standing outside of my Jeep at night when it happened, and I noticed rear tail light go out, so I assumed it must be electrical
not much help I know, but I would follow up the previous posters, measure pressure, new filter, change coil
01-12-2019, 10:32 PM
#12
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Year: 1992
Model: Cherokee (XJ)
Engine: 4.0
I replaced the distributor cap, rotor, and plug wires yesterday. Drove it about 25 miles today and it drove great. No loss of power. Hopefully that was it
01-17-2019, 09:49 AM
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Year: 1992
Model: Cherokee (XJ)
Engine: 4.0
Update: Drove it to work today, 45 miles. Cruise control set at 70, I had the loss of power issue again about 10 miles into the trip. It happens between 2k and 3k RPM. Happened a couple of times within a 2-3 mile window, and then didn't happen again for the rest of the trip. So distributor tune up didn't solve it. More troubleshooting required