I am trying to diagnose the issue here (video link below)
I ran the truck all last week and Saturday after cars and coffee. Came home parked the truck. Several house later went to go out again and was getting a firm clunk sound. All fuses are intact. Looked over the starter motor and no smoke or burnt wiring. Now as you see in the video i am getting the starter motor to spin and almost fire but not firing up. I believe it is the fuel pump or relay, leaning toward the relay because I typically hear the fuel pump turn on prior to firing and not hearing anything.
Just looking for confirmation, I’ve ordered a relay and it arrives tomorrow but curious what the group thinks.
Thanks!

 

I couldn't fully understand from the video, but if the vehicle is stopping by itself, first check the fuel pump and inspect the fuel filter.

 

Odd that you had a no crank over issue (loud clunk) to start with. I'd double check battery condition and connections, especially ground cable connection to frame/engine.

Then, if those check out...check for battery voltage at fuel pump, while cranking.

 

try some instant start spray see if it will start and then die - if so likely a fuel related problem - check fuel pressure at fuel rail - I assume you have fuel in the tank