Chevrolet Repair: not holding fuel pressure, fuel pressure gage, fuel pressure regulator

Question
ok please help I got a 1998 chevy 3500 7.4 thats hard to start. It takes about 10 seconds of cranking before it actually fires up. I changed the fuel pump 3 times, I changed my fuel filter, and I changed my fuel pressure regulator 4 times, and every time I hook a fuel pressure gage to it turn the key on and fuel pressue shoots up to 60bls and with in about 10 seconds the truck looses all the fuel pressure I don't know what else to do to hold pressure.

Answer
The pressure drop is either being caused by the pump assembly, regulator, or one or more injectors leaking.You will first need to determine where the pressure drop is at. There is a special tool that are hoses with valves in then to close off certain parts of the fuel system. If you have rubber hoses (not Plastic) you get a pair of pinch-off pliers. Pinch off the fuel hose right before it goes into the fuel pressure regulator. If the fuel pressure still drops after the key is turned on then it has to be in the fuel pump assembly because you eliminated the fuel pressure regulator and injectors. If it now hold pressure then it could be a leaking regulator and/or injectors.
Next pinch off the return hose after the regulator. If it now hold pressure it's most likely a defective regulator.

My past experience has usually led to the fuel pump assembly. Check all internal tank hoses for leaks.