Cummins x15 Derates. 50% Torque. 20psi boost

Truck Model 2020 Kenworth W900
X15 Cummins performance 605
....
The issue is this. The motor will seem to derate looses power. Torque will only go to 50% on gauge and boost to only 20 throttle will have very little response also it sounds like it starts running on 3 cyl. It will run like that for a bit then for no apparent reason will come back to life. It will do this over and over. Also when idling the motor will skip or what sounds like it almost slips. Iv noticed it starts harder takes longer to fire. We have had wiring issues plenty of them. Could this be also wiring or crank sensor ?

Truck has no engine lights or wrench lights either. Thanks for any advice