06 F-150 5.4L 3 valve 134K miles, Return-less fuel delivery system. DTC P0191 Fuel Rail Pressure A circuit sensor out of range/performance. I cleared the light it stays off on the first engine start but, relights at the second engine restart after 8 sec. Snap-On scanner troubleshooter states fuel pressure should be between 20-60 psi running. I installed my OTC fuel pressure gauge with in-line adapter, this type of fuel system has no schrader valve. KOER 85 psi.
The PCM controls the FP but what controls the fuel pressure? The FPS was replaced a few months ago with OE brand FoMoCo. Or is the FP spinning out of control. I have replaced many of fuel pumps and most of them have regulators, and tank pressure sensors installed with the pump assy. Replaced Air Filter & Fuel Filter. any suggestions would be greatly appreciated, Thanks.