1989 Jeep Cherokee hesitation and start up

1989 JEEP CHEROKEE
145,000 MILES • 6 CYL • 4WD • AUTOMATIC
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XGPA115
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hello, i have a 1989 jeep cherokee, with a couple issues. i have had it for about 2 years and i have experienced engine hesitation and lagging on start up. hesitation sometimes occurs while driving. i would drive for awhile and my engine would start hesitating without a known cause. i took it to a shop and the mechanic replaced the dying fuel pump. my car ran very nicely for about 6 months and started showing hints of hesitation, then while driving on a rainy day, my car began hesitating a whole lot and it couldn't really get anywhere, so i had a tow truck come and take it back home. the next morning i tried driving it and ran just fine! i don't get it, so i took it to a shop and the mechanic couldn't notice anything! *sigh* also, my engine lags while starting;i t's weird because it usually happens on warm and sunny days, around 70+ F degrees, i don't know if it's due to the crankshaft or starter, or something. so, i was wondering, what causes the random and mysterious hesitations and rough start ups of my engine and what can be done to fix these problems? i highly appreciate any feedback, thanks.
May 29, 2010 at 9:25 AM
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RASMATAZ
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Inspect and test all the following listed below

Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
False air leakage.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note:If it doesn't apply disregard.
May 29, 2010 at 10:48 PM
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XGPA115
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thanks rasmataz! and such a quick response by a master tech! i'll take good look around the fuel and exhaust components and have a mechanic take a look too. i don't think i need to check the common electricals on the list, i do that very often anyway, and they haven't been a year old yet. wish me luck
May 30, 2010 at 1:21 PM
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