Don't just load the parts cannon, troubleshoot it. If there is a restriction, no hard part will fix it. Three check points will give you the 4 readings you need, restriction into the system, lift pump output pressure/FF inlet pressure, FF outlet pressure, (pressure drop across the filter)gallery pressure.
You should check for air also, air will give you low pressure readings as will high restriction. Too much restriction can actually cause air in the fuel in the form of LOTS of very tiny bubbles, it makes the fuel look cloudy in the clear line.
View attachment 903535