Trying to help a good friend. I know nothikng about Duramax Diesels

Started acting up today, bucking and knocking, running terrible. Several Codes
from what I am looking at suspect bad ground or Computer Failure. Can someone take a look at the codes.

Truck has been running fine, on occassion thows abs light then clears it self. Heated seats work off and on. 04 Duramax with 133,000 miles.. Thanks!!

[PCM] P0208 - Injector 8 Control Circuit (SES) (History) (Immature)
[PCM] P0401 - Exhaust Gas Recirculation (EGR) Flow Insufficient (Old) (History) (Immature)
[PCM] P0404 - Exhaust Gas Recirculation (EGR) Open Position Performance (Old) (History) (Immature)
[PCM] P0670 - Glow Plug Module Control Circuit (Pending) (Old) (History) (Current) (Immature)
[PCM] P2149 - Injector Positive Voltage Control Circuit Group 2 (SES) (History) (Immature)
[PCM] U0073 - Control Module Communication Bus Off (History) (Immature)
[PCM] U0106 - Lost Communication With Glow Plug Control Module (History) (Immature)
[TCM] P0880 - TCM Power Input Signal (History) (Immature)
[TCM] U1255 - Class 2 Communication Malfunction (History) (Immature)
[TCM] U1000 - Class 2 Communication Malfunction (History) (Immature)
[TCM] C0306 - (History) (Immature)
[TCM] C0327 - Encoder Circuit Malfunction (History) (Immature)
[TCM] C0359 - (History) (Immature)
[TCM] C0379 - (History) (Immature)
[TCM] C0550 - ECU Malfunction (History) (Immature)
[TCM] B0790 - (History) (Immature)
[TCM] B2725 - ATC Mode Switch Circuit Malfunction (History) (Immature)
[Brake] C0055 - Steering Wheel Position Sensor Signal D (Old) (History) (Immature)
[Restraints] U1000 - Class 2 Communication Malfunction (History) (Immature)
[Entertainment] U1000 - Class 2 Communication Malfunction (History) (Immature)
[HVAC] B0229 - (History) (Immature)
[HVAC] B0414 - (History) (Immature)
[HVAC] B0424 - (History) (Immature)
[HVAC] B0408 - Temperature Control (Main/Front) Circuit Malfunction (History) (Immature)
[Convenience] B2425 - (History) (Immature)
[Convenience] B1960 - (History) (Immature)