This reminds me of my 12 valve swap. After it was put in, it ran good for a few months and then started acting up. If someone would have come by and made me an offer to buy the truck I probably would have sold it. I kept telling myself that whoever bought it would fix it for less than $10 and I would be kicking myself in the pants for not finding the problem and fixing it myself. After rebuilding the injection pump and 2 of the 6 injectors, it still didn't work. I talked to Cummins repair shop and after telling me that it was going to be $90 per hour to work on it, I decided that I could change a lot of parts myself for that kind of money. I changed the lift pump with no resolve before deciding to fuel the lift pump from a 5 gallon fuel can. It ran great and this helped narrow down my search. I bypassed the electric fuel pump, that the mechanic that did the conversion, placed between the lift pump and tanks with a piece of fuel line and two clamps. Problem solved. So for less than $10 I fixed it myself.
On this truck I am not sure what to do? It's a good thing nobody is close by waving money at me.
Maybe my flux capacitor is putting out too many Jigawatts??