1995 Jeep Cherokee missing, surging and bucking

Tiny
BOYDBALEX
  • MEMBER
  • 1995 JEEP CHEROKEE
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 108,000 MILES
My jeep has a missing or bucking problem, its does not do it all the time, mainly when the engine warms up, and it feels like a fuel starving problem. Under mild acceleration and steady throttle it starts to buck and surge. If I push the gas pedal to the floor it will accelerate just fine. The fuel pressure is steady at 40psi. It did have a code 52. I've changed the following parts: O2 sensor, fuel filter, spark plugs, plug wires, dist cap and rotor. Help.
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Wednesday, November 25th, 2009 AT 1:57 PM

3 Replies

Tiny
RASMATAZ
  • MEMBER
Oxygen sensor
Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires
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Wednesday, November 25th, 2009 AT 2:20 PM
Tiny
MERCEDESTECHIE
  • MEMBER
It is a "lean" condition prior to full warm-up.I posted a question to this site with the same situation and I was asked to "ohm the CPS (crankshaft position sensor) and get back to him" Apparently he was unable to connect the dots or read thoroughly. I'm a 30 plus year tech with euro cars, and I thought a Jeep tech might have seen this before. Good luck on finding the answer here.98 "lean" Jeep
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Saturday, December 12th, 2009 AT 10:18 PM
Tiny
RASMATAZ
  • MEMBER
Have you checked the crank possition sensor? If not unplug it and ohm it get back to me with the reading. It is on the left (drivers side) near the top of the engine on the back side just under the back side of the intake.

The CPS and the KS sensor will cause the same problem for the above problem
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Saturday, December 12th, 2009 AT 10:53 PM

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