Fmi 157 spn 18

[Hallmanhauling]

Hey guys I got a code on my truck for low fuel rail pressure. I’ve cleared it out and tried to make it come back up to see when it is happening. When I get on the interstate and do full throttle is when the code comes back up. I’ve replicated it twice already. I had an empty trailer. I replaced the high pressure fuel pump about 3 months ago and the rail sensor. I am at a loss right now as where to go from here. I don’t want to keep running the truck cause it won’t pull a hill for nothing when that code is on. Any help is appreciated.