Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Can you tell me how you are checking the fuel pressure?
Did you ever replace the filter after you had more problems?
The regulator is made to create a restriction so the problem could be the regulator, this is assuming there is not a leak someplace else, like a injector. I would start by finding a place to pinch off the return and see if the pressure goes up to normal or higher, if it does not I would check the oil to be sure there is not a bunch of fuel in the oil, that would indicate a leak into the engine. If the pressure does not go up and there is not a lot of fuel in the oil, I would start by checking the voltage to the fuel pump, if that is good I would check the ground to be sure it is good.