I'm looking into the same thing- what the correct fuel pressure is for the eec 4 5.0L.
Is the aftermarket rising rate fuel regulator necessary? I thought that if it's regulated to the specified pressure- the injectors would operate correctly. I mean, it's the EEC that is adjusting the injectors movement electronically, not by changing the pressure (mechanically).
Apparently, the factory FPR is adjusted by engine vacuum also.
