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JEEP PROBLEMS>>>>>ADVICE WANTED
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chubbyt
New User
Jun 30, 2007, 9:41 AM
Post #1 of 5
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JEEP PROBLEMS>>>>>ADVICE WANTED
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I own an old 87 Jeep Cherokee "limited"(it really is) with 100k on it. Straight six 4.0 injected, automatic. For the last few weeks it's been having misfires (no backfires) and trouble staying alive at cold starts, which lasts about twenty minutes. It also does this at warm starts, but reduces in extremity faster than when cold started. If driven, its chugs and hesitates under load, acceleration, etc... It intensifies if you're cruising at low rpm and lightly increase the rpm towards a down-shift. It bucks worse than my last girlfriend. If it is running in park and as the motor is quickly revved up and quickly let to go back to idle, the motor almost stalls out and has trouble finding its idling point. I've replaced the fuel filter, checked all fuel injectors and have changed those deemed to be too old. I've checked the distributor cap and replaced all plug wires. The plugs are Bosch and were replaced 5000 miles ago. The fuel tank is full (I'm not a complete moron) and doesn't seem to be vapor-locking. It's not causing any more motor noise and seems to be in the fuel or air induction system. Any ideas of what this could be? I appreciate all your help...
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jun 30, 2007, 10:19 AM
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Re: JEEP PROBLEMS>>>>>ADVICE WANTED
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I'd start with checking the fuel pressure. I recall some trouble with the intake manifold on this engine but that problem is not really consistant with your complaint. If you spray carb cleaner at the gasket between manifold and head and the engine speed reacts to that there would be a problem there. Careful as exhaust is there too and carb cleaner is flammable so go easy it you try that, T
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thomas74
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Sep 3, 2007, 5:03 PM
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Re: JEEP PROBLEMS>>>>>ADVICE WANTED
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i would do a good tune up and replace the crank sensor
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Guest
Anonymous Poster
drew14326866@yahoo.com
Apr 5, 2009, 5:38 PM
Post #4 of 5
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Re: JEEP PROBLEMS>>>>>ADVICE WANTED
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If anyone else has this particular problem (engine trying to stall, or dying when you release throttle, or any of the things this gentleman mentioned), the problem may be inside the fuel tank. Trash and corrosion can stop up the intake at the fuel pump and on older models, prior to the submersible fuel pump, the sock at the intake line. The only solution is to drop the tank and empty it. Clean out all debri and replace the sock or eliminate sock and add another fuel filter inline between tank and motor mounted fuel pump. On the older motors also make sure that any rubber hose in supply line, from tank to fuel pump, is in good condition and if in doubt at all just replace them they're not expensive. If not, the deteriorated rubber line will easily colapse from the vacuum within itself and again cause a motor to stall or die. If this was the cure, your motor WILL run better. Throttle response and power will be retored immediately.
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Loren Champlain Sr
Veteran
/ Moderator
Apr 6, 2009, 3:27 PM
Post #5 of 5
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Re: JEEP PROBLEMS>>>>>ADVICE WANTED
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chubby;>>It bucks worse than my last girlfriend<< That's one of the best descriptions I've heard! Gets me right to the point. If the engine runs 'fine' after warmup, I'd take a look at the coolant temp sensor. If you have a scanner available, you can 'see' what the computer is seeing for actual temp. If not, you can check resistance of the sensor with an ohmmeter at different temps. Almost always, when a CTS takes a dump, it defaults to COLD, as in -40F. That's okay if you are in Fairbanks in January. If it still doesn't run okay after complete warmup, I'd still check the CTS, but could be other issues, as well. Usually, electronics will act up after reaching temperature. Rarely, when cold. But, still possible. Loren SW Washington
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