[ford38v8]

There will be those who deny the existence of vapor lock, but your IR temperature gauge tells the story. Under-hood heat soak raises temperatures to the point that fuel flashes from a liquid to gaseous state in the system, causing fuel pumps to lose their prime: Liquid fuel does not compress, while gas (no pun intended) readily expands and contracts, failing to open and close the pump's valves as designed. While it's true that there are other causes for the symptoms you've experienced, modern fuel evaporates at a much lower temperature than in the days before Ethanol (dirty word), vapor lock is my guess and I'm sticking to it.