The FICM solved the problem. I let it idle and come to temperature, then went to pushing and wiggling all the wires I could just to be certain!
For this bad FICM, I purchased it refurbished back in 2019 and it bothers me it failed that soon. I don't use this truck that much, but since I'm selling my 2016, I will be using this full time again until I decide on a new one. I know these trucks don't like to sit as I've had my fair share of problems from it sitting.
So to summarize and to help anyone else out:
Initial problem was it went into limp mode while driving. When I finally got to a safe spot to stop, the truck would hardly move and sounded like a forklift/tractor
Was able to get it home, maybe topping 25mph. Pulled the codes and it was P0202, P0208 and P02149. I never ice picked the truck before, but I had done all the preventative stuff on the wiring harness - ever more so after my TCM failed.
I ice picked all the injectors just to get it out of the way. Paid special attention to #2 and #7. They looked fine. #5 had diesel inside the connector. I guess from all the priming over the years it finally got through the seals. Sprayed this out with some electrical cleaner made for sensitive electronics.
Truck ran fine for about a month.
Time to sell other truck - need to get this one more friendly for daily driving
Removed 68mm turbo and installed 64mm, completely removed the EGR, HSP Y-Bridge installed, new passenger side manifold and up-pipe with no riser. Batteries were disconnected the whole time.
Fired up with no issues, did have a strange sound, but I didn't have one of the exhaust to up-pipe bolts tight enough. Took it for a couple easy rides to get the fluids hot and work in the turbo.
As I'm home getting ready to put my fender liners in - BAM, tractor mode again. This it when it threw all the codes. for the B bank Injectors along with the P02149
From the top C1 and C2 connectors on the top driver side, I completely removed the harness from both sides of the engine and did insulation and continuity testing on each wire, even the bank of injectors that had no problems. Each wire checked out perfectly. Replaced the #2 and #5 injector plug. All the others were fine when checking pin to pin. Checked resistance between all the injectors, all were either .02 or .03ohms.
Verified the ignition power to the FICM, which is one of the big pink wires on the bottom of C2. No issues. Assembled everything back together and it ran for 10 mins and was back in limp mode. Cleared the codes and it would do it at random intervals. Didn't matter if I pulled or wiggled wires, it would just do it out of no where. This is where I suspected the FICM was bad. My fuel light was also on, showing no fuel, and my Range had - - - across the DIC.
I don't know how much I trust this used FICM as I got it off eBay. I will send my other one off to be worked over. I may do the same to this one, or just let it ride. They are definitely not cheap and are hard to come by. Stuck between keeping this as a spare, or refurbing it and selling.
Either way, I hope this helps someone out. This troubleshooting took me from Thursday to Sunday. I've also attached the electrical diagrams which are very helpful.