Does this truck have a longer than normal crank time when its first started???
If the A/F ratio is going high,possible causes are intake air temp sensor......MAF sensor...is it dirty??? Can you check O2 sensor and see if it is switching back and forth??
Another possibility is the assistant injector leaking or not working properly as well as main injector issue....or a pressure relief valve in the injector holder is sticking open some.....with the engine off and key on do you hear fuel going thru injector and intake and going past relief valve......there are two relief valves in the injector holder...might be good idea to remove injector holder remove main and assistant injectors and clean the injector holder of gum and tar...also check fuel PSI...should run around 4.5-5 PSI