You can choose to accept my answers or not and I understand that. However, I can only give you my experience and try to relay that information to you. None of the information was fuel related, all of it was computer related as you must remember the computer is what controls the fuel flow. The computers job is to dispense and modulate the fuel flow to maximize economy, power and emissions. Three very different things.
What I do find interesting is just how reliable vehicles have become and the effect that it has upon us owners. 20 years ago, had a vehicle quit running, we as owners would have put the vehicle into neutral and attempted to restart the car or truck. If it had started, we would have put it into gear and carried on our merry way and not given it a second thought. Today it is a catastrophic failure.
All of the scenarios that I gave you apply to your situation as do the ones that the dealer gave you. I am sorry that neither I nor the dealer seems willing to tell you that there is a part that needs to be replaced on your truck. I think that is what you are looking for and that is what you pretty much stated.
Todays vehicles run for 100,000 miles with out so much as a tune up, start without touching the throttle pedal, idle perfectly 95% of the time, rarely hesitate or bog down, get decent fuel economy considering the load that they are required to haul, run hard when required, rarely overheat, and handle pretty much what ever we throw at them, whether that is in the city and stop and go traffic, or on the freeway, cruising at 70 mph with the A/C on.
And yet. It almost makes me long for the old days, where a vehicle had to be tuned up twice a year, it would take 5 minutes of high speed on the choke before you could put the engine into gear, the carb had to be adjusted when going from sea level to the mountains and when a truck would get 7 mpg, with no a/c, no cruise control, no load, and no comfort.
Goosing the throttle, is not the same as giving it a wide open throttle pull. I am talking about full throttle acceleration on a on-ramp type of pull, 10 seconds or more.