2005 14L Series 60

[TomHanson]

Engine runs rough. In the past 4 months, I've replaced #1 and #3 injectors two separate times. This would instantly fix the rough idle, and cure my "injector #1 response time long" fault code. Now, the same issue is happening. Went through all ecm data to find fuel temp and ambient air temp show -40 degrees f, which were the only odd things I could see. Truck came in this time with a plethora of inactive faults, and 3 active for injector 1 - response time long, fuel temp sensor - input voltage low, and oil pressure high. I'm leaning towards something in the harness at this point, I was curious is someone could get me some troubleshooting trees for these to at least point me somewhere? Or give me some input on some things to check...