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jeep bucking/ stalling

raze1287

NAXJA Forum User
Location
Danbury Ct
I got a 1993 xj 4.0 been having a problem recently it seems sometimes when it warms up it will buck, misfire, pop through the intake and sometimes stall. The tach will go crazy while doing this will drop to 0 then up to where it should be multiple times then be fine if it continues running or stall. Seems to randomly happen when im around 1500 to 2000 rpms. But it always fires back up right after it stalls. Has a new coil and fuel filter. Any ideas?
 
when this happened to me it was timming.
 
The fact that you noticed that the tach sometimes drops to zero points to a possibility of a flaky crankshaft position sensor.

Your other symptoms also point to a thermal fail (heat related fail) of that sensor, including when it stalls. The crank sensor is prone to thermal failure when they get old.....
 
The fact that you noticed that the tach sometimes drops to zero points to a possibility of a flaky crankshaft position sensor.

Your other symptoms also point to a thermal fail (heat related fail) of that sensor, including when it stalls. The crank sensor is prone to thermal failure when they get old.....

Agree with BirchlakeXJ. Another possible candidate for the thermal failure is the coil. IF you had a Renix I would suspect the coil due to the tach drop off--the Renix tach reads off the negative side of the ICM/coil, but your not Renix and I'm not sure on the OBDI where the tach signal is read from.

Good luck.

Strangely motivated enough to look up the tach signal source for the OBDI in the 95 FSM--it comes from the PCM.
 
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Agree with BirchlakeXJ. Another possible candidate for the thermal failure is the coil. IF you had a Renix I would suspect the coil due to the tach drop off--the Renix tach reads off the negative side of the ICM/coil, but your not Renix and I'm not sure on the OBDI where the tach signal is read from.

Good luck.

Strangely motivated enough to look up the tach signal source for the OBDI in the 95 FSM--it comes from the PCM.

I thought it may have been the coil at first so i threw a new one in and it made no difference

Bucking like a horse; and stalling like donkey?

My '93 XJ did this a few months ago.

A new Throttle Position Sensor fixed it right up.

Thats kind of what i am leaning torwards. It never happens when im any where near home so it is kind of annoying.
 
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