JEEP GC STALLING

I AM A MECHANIC AND I HAVE COME ACROSS THIS PROBLEM.THE OWNER OF THE JEEP HAD TRIED WITH ANOTHER SHOP THE SAME FIXES THAT ARE POSTED ON THE FORUM.
CHANGING THE SPARK PLUGS, CRANK SENSOR, CAM SENSOR, DISTRIB. CAP & ROTOR, SPARK PLUGS & WIRES, & THE COMPUTER TWICE, FUEL PUMP.
I FOUND THAT THE PROBLEM WAS IN THE WIRING HARNESS AT THE COMPUTER.AT THE ECM THERE ARE 3 PLUGS THE PLUG CLOSEST TO THE FENDER COULD BE MOVED JUST SLIGHTLY AND IT WOULD GO DEAD.
I SUGGESTED CHANGING THE PLUG END.
I ALSO FOUND THAT I COULD PULL THAT HARNESS UP AND HOLD IT TIGHT AND THE JEEP WOULD STAY RUNNING.
THE CUSTOMER WOULD NOT LET CHANGE THE WIRING PLUG END AT THAT TIME SO I TIED THE HARNESS UP TIGHT WITH A PIECE OF WIRE.
THAT WAS LAST MONTH AROUND THE FIRST WEEK I HAVE SINCE TALKED TO CUSTOMER AND HE SAID THE JEEP WAS STILL RUNNING FINE.
PLEASE LET ME KNOW IF THIS HELPS.