i have a '96 xj that wouldn't start. the batt and starter tested good. i installed new batt terminals, batt, and starter anyway, because the starter would not spark when i touched a screw driver to it. it started and ran for a few weeks. again will not start.... i go to start it in the morning and nothing. no clicking and doesn't try to turn over. i have all lights, radio, wipers, just no start. i go to get my girlfriend to take me to work and while she is getting ready i go back to try again and it starts. nothing was changed... did this for two days the third day it was done playing around. i touched a screw driver to the starter to see if it could be the starter again. it sparked. i went to start it and it fired up no problem, a few times not back to back. i waited a lil while between. i waited a long time in between, about an hour or so, and went to look at it again because nothing was changed and i worried about it starting tomorrow morning. it started and the struggled to stay running and shut off. i tried again and would turn over but had to hit the gas for it to start. so it starts now butif i rev to 2000 and let off it dies. i can let off very slowly and it stays running. i'm at a loss now.... ha please help.

 

Had the same issue, changed batt, starter, cleaned the NSS and changed the cables (positive & negative.)
Didn't go away until I replaced the relays in the power distribution box.

 

Was that battery "LOAD TESTED"? Voltage testing by itself of a battery can be inconclusive.

A marginal battery is a common cause of stalling.

If battery is verified good, then try cleaning the throttle body and idle air control. More on that below. Be sure that all tuneup hardware is fresh. That includes fresh Champion copper plugs gapped to .035, new wires, distributor cap and rotor.

After that, time to verify fuel pressure with a fuel pressure gauge (you want 49 psi at idle for a 96). Then test your throttle position sensor.
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The Idle Air Control (IAC) is mounted on the back of the throttle body. The valve controls the idle speed of the engine by controlling the amount of air flowing through the air control passage. It consists of a stepper motor that moves a pintle shaped plunger in and out of the air control passage. When the valve plunger is moved in, the air control passage flows more air which raises the idle speed. When the valve plunger is moved out, the air control passage flows less air which lowers the idle speed. Over time and miles, the IAC can get carboned up which can have an adverse affect on idle quality. Cleaning the IAC may restore proper function and is an easy procedure to perform and good preventive maintenance so it is never a bad idea.

CLEANING THE JEEP 4.0 IDLE AIR CONTROL

Remove the air filter cover, associated hoses and the rubber boot that goes from the air filter cover to the throttle body. Remove the IAC with a torx driver (2 bolts; one can be kind of hard to get to)

“Gently” wiggle out the IAC from the throttle body. Gasket on the IAC can be re-used if it is not damaged

Clean the IAC with a spray can of throttle body cleaner; inexpensive and available at any place that sells auto parts. Throttle body cleaner is recommended rather than carburetor cleaner as it is less harsh, safe for throttle body coatings and is best for this task. Use cleaner, a rag and a toothbrush and or Q-Tips. Be gentle; don’t twist or pull on the pintle that protrudes from the IAC as it is fragile and you could damage it.

Thoroughly spray clean and flush where the IAC seats in the throttle body with the same spray cleaner

It is also a good idea to clean the entire throttle body itself, the butterfly valve inside of the throttle body and all associated linkage as long as you have things disassembled

Reinstall IAC and check idle quality