Alright i have a 1992 jeep cherokee limited with an in-line 6. i had over heating issues so i replace my water pump, easy fix. let the car sit for the glue dry. next day went to the gas station filled up and went up a couple mountain passes to check the cooling system turned out the water pump did not fix the problem. thinking its the raditaor cap. anyway thats not why im here. after that replacement drove to work after work jeep started but died within seconds. Tried it again with pumping the gas pedal turned over but died instantly! thought it was the cps replace it a day or two ago and did not change my situtaion.
HELP!

 

hows your battery/alternator? mine was doing the exact same thing, and the battery was completely flat. after putting it on a charger overnight it ran fine

 

NSS maybe? My ignition module was boogered up a bit and had same symptoms until i replaced it. It would die on me but if i held the key half way between ON and START it would hold a connection and stay running. (Not engaging the starter) That wasnt easy to drive 6 miles home on the trail when it happened.