1997 sport, problem stalling

I have tried everything that I can think of to fix this, but I have a 1997 cherokee sport on the way home on the highway it started to loose rpm and then soon died, let it sit a bit and then it started and I drove home. It now has gotten worse since then, it will start again and then die within usualy 2 miles, I have changed out plugs and wires, cap and rotor, I have removed the cat to check it and it is good. I have not changed out the fuel filter, I am starting to think that It may be the fuel pump or just the filter I have the filter but I don't want to take down the tank that bad, but whatever, any Ideas before I dive in to the tank... also, can you replace just the fuel pump in the module or do you have to replace the whole mod. any help will let me get back on the road.

thanks Mitch.

Sounds like a fuel pump.. You can just replace the pump. The next time it quits ,check for fuel at the rail.

Good Luck
Nick

Start with all the cheap and easy stuff. Remove, clean, inspect, and firmly re-attach all the wires to your battery, alternator and starter. Repair or replace any wires or connectors that are corroded or damaged. Locate and do the same for the three under hood ground wires. The 4.0L ECM/ECU does weird stuff when faced with low voltage. Have the battery load tested at the parts store. Clean the throttle body and IAC. Test the CPS and the TPS. Consider replacing the Camshaft Pickup sensor in the distributor housing. Consider replacing the Coolant Temperature Sensor. You might suspect that one or more of the sensors is sensitive to under hood heat. When it gets warm, you shutdown, when it cools, you can re-start.
Monitor the fuel pressure before you drop the tank.

As Tim mentioned, this really sounds like a classic "thermal failure" where a component fails when it heats up.

The problem with "testing" for a thermal failure is this. Unless you are quick with a meter, by the time you end up testing a sensor or if you test it in the driveway cold, it will probably test out just fine because it is NOT HOT any longer. That makes isolating thermal failures tough sledding. I'd still recommend testing though if you can make the arrangements to do so immediately upon failure.

My first instinct is that you may have a bad crankshaft position sensor. In my opinion, it is THE most common sensor failure on the Jeep 4.0 I've included a procedure for testing if you're so inclined.

I'm not a big fan at all of the strategy of "throwing parts at it" but in this unique situation, if you don't stumble onto the problem, installing a new crank sensor may be a good strategy. As they are such a common failure, even if it doesn't fix your problem, it's not money wasted.

BTW, "most" people replace the entire fuel pump assembly (pump/regulator/filter) on this vintage as the gas tank has to come down but I believe it can be repaired individually but for obvious reasons, consider doing the entire assembly.

Good luck and post back what you find!

Crankshaft Position Sensor: Common Symptoms if bad:

*Both the fuel gauge and or voltage gauge may not work/display

*It is possible that you may see a No Bus on the odometer

*You will have no spark. Fuel pressure may check okay but fuel won’t get to injectors

*Sometimes the OBDII code reader has trouble connecting to /reading codes

*Crank sensors can be intermittent; "thermal failure" is pretty common. Means that the sensor fails when engine gets hot, but works again when cooled back down. Be aware of this when testing as if you have a sensor that suffers from thermal failure, it will probably test GOOD as soon as it cools down.
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CPS TESTING PROCEDURE 1991 – 2001 4.0L H.O. engines

1. Near the rear of intake manifold, disconnect sensor pigtail harness connector from main wiring harness.
2. Place an ohmmeter across terminals B and C (A-B-C) looking into connector left to right with the part with the notch in the middle on the right) Ohmmeter should be set to 1K-to-1OK scale for this test.
3. The meter reading should be open (infinite resistance). Replace sensor if a low resistance is indicated.

Thanks folks I will give it hell and then report... BTW my code reader is telling me that it is haveing a misfire in cylinder 1 and 2 and then also reports random misfires, I am not getting any other codes to report, and the repair options for P0300, p0301, p0302 are near 100 so I appreciate all the help, if that little tid bit helps I'll check for an update tomarrow night.. thanks again
Mitch