1998 Astro Van 4.3 Vortec has fuel delivery problem.?

vortec systems must have 54 psi.. if the system has 45 it still will not open the injector pop-its.. look to the pump, very common on GM vortec trucks.. only put ac delco pump in the van. after market pumps do not last.. also if you can do a dead head pressure test... meaning test the fuel pressure before it gets to the filter with no return to the system.. this will give you a true reading and remove the possibility of a bad fuel pressure regulator.