E...G...R... tube???? Ummmmmmmmmmmmmmmmmmmmmmmmm...................next.
Different IDM but same problems? Not the IDM (if you're sneaky give your friend back the 100v IDM from your truck and keep the 110v

) (Start on the right side as the Ford "diagnostic" was seeing trouble codes from that side. I'm also assuming that the internal work you already did is tight and routed away from the moving parts)
First, do you have a infrared temp gun? If so while idling shoot each side of the exhaust as close to the head as you can get to each cylinder. Seeing a cold or hot cylinder will greatly speed up your diagnosing time.
Second, using the attached P.O.S. wiring schematic, remove the connectors at the heads and at the IDM. The Orange and Pink/Yellow wires _shouldn't_ be your issue as these are shared with the rest of the right or left injector banks but with each wire in turn put a meter (set to Ohms scale) on both ends and read the resistance. You shouldn't see more then .2 Ohm but at the very least they should all be the same resistance.
With the engine running/idling climb on top of the motor. Starting on the right side by the wiring connectors on the head move the wiring harness up/down/left/right. Nothing happened (runs better/worse) move two inches down the harness (closer to the IDM) and do it again. You are chasing a short in your system like this. Ford actually calls this the Ford Wiggle Test (yep, it's in the Ford manual). If there is a short/open in the wiring you'll know when the symptom gets better/worse where you are wiggling the harness. If the truck has had a fuel leak in the past and it wasn't thoroughly cleaned up the diesel fuel slowly eats away the wires shielding and shorts it to the next one. Most likely in the valley close to the fuel system. Be careful as the motor is hot.
Find anything?