2018 t&d otherwise stock. 160k with FASS 165g. Truck experiences some weird fueling if you just stab the pedal 50+%.
To give some back story. Installed FASS 3 years ago. Ran flawless. Starting having a weird rail pressure actual versus demanded drop I can see on the monitor. Basically if you are at a stop and pin it…the rail pressure will crash(under 4k) or sometimes same issue if you 50-75% throttle on highway..not enough to make truck downshift and grab rpm..after a second it catches back up and leaves out. Truck does this the WORST running FASS filters. Bought some fraud fass filters that killed the pump. Talked with fass, sent in pump and pump tested bad…Replaced pump…now any fass filter duplicates issues out the gate…I can run Baldwin 7633’s and 1258’s and they will run fine for a month. Then THEY have same “fall on their face” issues. Fass instantly blames the truck -_-
I have
-replaced fass pump
-checked battery and alternator good
-replaced relay
-redid hoses and checked all connections for leaks
-performed bucket test for cavitation…passed
-no codes at all. No prv codes. No cp3 codes. No fca codes.
-i have confirmed 12v at fass pump and checked over all connections

really at a loss here and worried about the cp3?