SlipperySquid
NAXJA Forum User
- Location
- Orange County, CA
Three months ago I changed my U-Joints. During the test drive, the engine stumbled for the first time. I was accelerating hard and the engine briefly cut out a couple of times. This was the beginning.
Now I experience random sputtering, stumbling, and even violent bucking under acceleration. Occasionally the bucking will kick in when I'm cruising on the freeway. This seems to be completely sporadic and I can not find any pattern. Sometimes the Jeep drives fine and you would never know there was a problem. Hot or cold makes no difference. Here is the kicker... it drives fine in reverse. I can floor the pedal and she takes off anytime and everytime without any problems.
Thanks to all of you with similiar posts and a big thank you for all of the insightful responses.
1991 XJ 4.0 HO AW4
What I have checked:
-Air Filter is clean
-No Vacum Leaks. I used a can of carb cleaner and vacum gauge.
-Fuel Pressure is good.
-Replaced fuel filter
-Coil tested bad. Replaced. Same problems.
-Replaced TPS No joy
-MAP sensor is good
-MAT sensor is good
-Unplugged each injector to see if leaky injector was the culprit... no dice
-Replaced cap and rotor. Just because
-Misted distributer cap and plug wires with water in the dark with engine running. No arcing found.
-On a hunch, I replaced the fuel pump. Everything was fine for a few days and then all problems returned.
-O2 sensor is less than 6 months old. I'm assuming it is not the problem.
-Yes, I have also used injector cleaner.
-There are no fault codes.
-No check engine light.
I suspect the Cam Position Sensor (CPS) or maybe the Crank Postion Sensor.
Did I omit any pertinent information?
Keep in mind it runs perfectly in reverse!? Any Ideas?
Please, Please, Please, Help!!
Now I experience random sputtering, stumbling, and even violent bucking under acceleration. Occasionally the bucking will kick in when I'm cruising on the freeway. This seems to be completely sporadic and I can not find any pattern. Sometimes the Jeep drives fine and you would never know there was a problem. Hot or cold makes no difference. Here is the kicker... it drives fine in reverse. I can floor the pedal and she takes off anytime and everytime without any problems.
Thanks to all of you with similiar posts and a big thank you for all of the insightful responses.
1991 XJ 4.0 HO AW4
What I have checked:
-Air Filter is clean
-No Vacum Leaks. I used a can of carb cleaner and vacum gauge.
-Fuel Pressure is good.
-Replaced fuel filter
-Coil tested bad. Replaced. Same problems.
-Replaced TPS No joy
-MAP sensor is good
-MAT sensor is good
-Unplugged each injector to see if leaky injector was the culprit... no dice
-Replaced cap and rotor. Just because
-Misted distributer cap and plug wires with water in the dark with engine running. No arcing found.
-On a hunch, I replaced the fuel pump. Everything was fine for a few days and then all problems returned.
-O2 sensor is less than 6 months old. I'm assuming it is not the problem.
-Yes, I have also used injector cleaner.
-There are no fault codes.
-No check engine light.
I suspect the Cam Position Sensor (CPS) or maybe the Crank Postion Sensor.
Did I omit any pertinent information?
Keep in mind it runs perfectly in reverse!? Any Ideas?
Please, Please, Please, Help!!