I just put in new 4-port injectors, and every so often, when pulling out from a stop in 1st gear, it stumbles. As soon as it gets more rpms it is OK and continues to be OK through all the other gears. I have new plugs, wiring, and a new fuel pump and filter. The fuel pump pressure at the pump is 100psi. At the rail, it is only about 29psi. It used to be 39psi. I replaced the pressure regulator with one that is supposed to be OEM, but I think I need to find one that has a higher static... Is there a pressure regulator that puts out 39psi?