I have a 14 f150 5.0 and iv come across a issue that I have been unable to find a solution the truck will crank and run when cold but after a heat cycle the truck will crank no start until it’s cooled for about 30 mins to an hour iv gone down the rabble hole of basic solutions fuse 27 was relocated, new fuel pump, fuel pump module, crank sensor and even purge valve. There are no codes and truck runs absolutely fine when does start. When looking deeper when testing injector power I’m only getting about 3 pulses then dead then cranking I’m lost at where to look into next maybe heat soak to the pcm or cam sensors getting hot any input or similar situations would be greatly appreciated thank you.

 

I'm not sure I can help you, but members have had the no pulse problem.
The pulse is controlled in the PCM with it switching to ground to complete the circuit.
The ground points that I see pertaining to the PCM are:
One on the firewall near the PCM.
One on the passenger fender near the battery it looks like.
Also the ground for the fuel pump module on the cross member above the spare tire.
Maybe be sure they are clean and tight.
You could also pull the connector at the PCM and inspect it.
I think that pulse signal is only 5 volts as I recall.

I have read something about the throttle control too.
When you put it to the floor it cuts out the injectors.
Maybe check that connector and or try flooring it and releasing while cranking to see what happens.

In the old days what you described (minus the pulse info) it would sound like a vapor lock type thing with the fuel.
Do you smell any fuel when this happens?
If yes you could have a leaky injector.