I have a 91 suburban and I am getting what feels like a miss under load. I have done all the tune up parts and it still has this missing problem. I have tested the fuel pressure and it has 11 psi ( spec is 9-13psi) when the key is turned on. It then drops to 2psi when the key is turned off. When driving and I accellerate the pressure does not increase. At w.o.t it will drop about 1-2 psi. I blocked off the return line and the pressure went to 16psi and did not drop off. Here is the question. Does the fuel pressure need to increase when accellerating? Should the system hold the pressure when shut off? . I think I need to rebuild the FPR. My friend thinks that is not going to correct the problem. Please help us settle this.. Thanks for your help.

5.7l tbi auto trans 3/4 ton 4x4 no cel no codes