1995 CHEVROLET C/K PICKUPS Electrical System Problems

I HAD A CHEVROLET PICKUP 1500 WITH THE TURBO 6.5 DIESEL ENGINE. I HAD PROBLEMS WITH IT FROM DAY ONE. I WOULD BE GOING DOWN THE ROAD AND THE ENGINE WOULD SHUT OFF AND TURN ON BY ITSELF. WHEN I TOLD MECHANICS, THEY LAUGHED AT ME. CHEVROLET TOLD ME IT WAS THE FUEL INJECTOR, I CHANGED IT,DIDN'T MAKE A DIFFERENCE. THEN NO CODES WOULD COME UP WHEN ON THE TECH'S COMPUTER, EVEN WHEN AUTOMOBILE REPEATED PROBLEM. IT WAS ASSUMED ON MANY OCCASIONS WHAT IT WAS AND AT MY EXPENSE I CHANGED MANY PARTS THAT NEVER MADE A DIFFERENCE. I WAS TOLD THAT IT WAS PROBABLY THE WIRING HARNESS, BUT COULD NOT BE GAURENTEED BECAUSE NO CODE CAME UP. THIS WOULD HAVE MADE IT AN ELECTRICAL PROBLEM. I COULD NOT AFFORD TO KEEP SPENDING MONEY. I'M A SINGLE PARENT AND THIS TRUCK WAS HOW I MADE MY LIVING.(I HAUL OILFIELD EQUIPMENT)....