power loss on d12

im trying to figure out why this truck lost all of its power. its a d12c. driver says he has to use 1st gear to make it up hills and its only boosting 15 psi. and i can feel like its sluggish when driving around the yard.

im getting a code PID 094, and it has new fuel pump. i dont have the correct tools to check actual fuel pressure, but i didnt put in a different fuel pressure sensor that i assumed worked, with no change.

can it be the wiring for the fuel pressure sensor?

 

i just checked fuel pressure and its 55 psi at idle and 75 driving up to 3rd gear (thats all i can do around the yard). that seems a bit high. is it possible a clogged fuel injector to cause this?

 

driver says its doing about 15psi max. and i havent found any leaks

 

ok so i found out that the ecu was not getting a reading from the fuel pressure sensor. i was sure that would fix it but it didnt. 3 of the 4 wires were open circuit on the fuel pressure sensor
it only starts building boost at 1800 rpm and only to 15psi.

is there a way to check injectors?