I had the same symptoms a few months ago and it turned out to be the fuel pump. Some days it worked with no problems, the next day the GC would die and not restart. There was no consistent pattern. I spent a lot of time diagnosing everything. I replaced the fuel pump and have not had a problems since. When it will not start, have you tried turning on the ignition and listening for the fuel pump pressurizing the system?
2001 GC Laredo 4.0 4x4 - Black l 2001 GC Laredo 4.0 4x4 - Silver