I recently purchased a 2008 F150 5.4 It keeps throwing code P0193 Fuel rail pressure sensor The truck runs fine it's just that it sets the check Engine light
I replaced the fuel pressure center on the rail Within after market one made by standard I also checked that there is vacuum there What else should I be looking at

 

Have you monitored the fuel pressure? If it is solid I would say it could be a wiring problem with the sensor wiring.
if pressure is not solid inspect the fpdm.

 

What's should the fuel pressure be at idle

 

39-45 psi in that range solidly

 

The P0193 indicates an electrical circuit fault with the FRPT sensor. It won't be caused by the FPDM or an actual fuel pressure issue. Here's the intro to the diagnostic procedure that explains the DTC and what causes it.

 

Thanks do you have the rest of the diagnostic chart

 

Ah. I must have been thinking of p0191...

 

I'm following along with this. I currently have a crank/no start with the same p0193 code on my 2004 f150 4.6. Except I have normal pressure (38-42 pounds) key on/engine off but then it ramps up to 55-65ish and spikes at 79.8 psi during cranking. Using Innova 3040rs scan tool to monitor fuel pressure. Kinda baffling to me. Hopefully you get your problem figured out. Post updates if you can.