My 1996 GC ran fine one day but the next day it wouldn't start. It would crank over but never fire. After much research on the internet I narrowed it down to the Crankshaft position sensor. Checking the sensor was easy. Unplug it from the wiring harness, then while looking into the plug at the three prongs with the locking clip up, the middle and right prongs should show an open circuit when tested with an OHM meter. Mine showed closed, so I took it one step further and pulled it from the bell housing and checked it again with the end of sensor touching metal and got the same result. Bought a new sensor and tested it and got the open circuit that confirmed that I had a bad CPS. Installed the new one and the old jeep runs like it did before.
Thought this might help someone save some time and headaches.