Currently having an issue where the engine will crank no problem but will not turn over or start. Here is the history of the issue:

2 weeks ago I noticed that it was having more laboured starts, it would take twice as much cranking to get the truck to fire up. Assuming the spark plugs were end of life, I replaced them. (I've already done the coils 35k miles ago). I started with no issue, and I ran it until warm then shut it down.

New day, went to start it, same laboured starting issue but ran no problem and after the truck was warm the issue didn't seem to persist.

Two days later, full crank but no start, and now thats where it is.

Here is everything I have checked:
- swapped the EFI relay to check for a failure
- Repeated everything with the spark plug install - no obvious problem signs on the new plugs
- Checked all the fuses in the engine and cab

NOTES:
- when the key is turned to ignition, I cannot hear the fuel pump start
- In park, with the key turned, the truck throw the code P0340
- Tried starting with starter fluid, with the plastic ducting off the intake manifold, tried to turn over and then shot white smoke out of the intake manifold... could be a timing / cam position issue?

Unsure if I should proceed by chasing the fuel pump as an issue or chase the Camshaft position sensor as an issue. Any guidance on where to do next would be super appreciated.