CM871 Slow Climbing Regen Temps

[Taco05]

Yeah it's something that we never needed to succeed in this industry but unfortunately we have to fight with it now.
I know now that my aftertreatment issues are caused by poor performance of the engine more precisely the fuel system.

Now I have tested both banks for injector failures and no air out of either bank during the test on any injector (engine cranking at 10 sec intervals) but still when I do a cutout test my 4,5,6 cylinders dont make any change in engine idle performance. I can actually cut out all 3 injectors (bank2) and I cant feel any difference and the RPM's stay the same. Still hear the solenoids clicking a lot and very rough idle or stumble.

I am looking at the solenoid wiring everything looks fine and there are no codes for the fuel solenoids or any fuel related codes.
I am wondering if the IFSM could be bad and not throwing any codes.