truck failed to start - low fuel pressure?

[Erik the Awful]

Intermittently doesn't want to run and backfires? I'd suspect an ignition issue before a fuel issue, specifically the ignition control module.

 

[Chris253]

O.P.: you mentioned 4AM. What's the significance of 4AM?
Does it start perfectly fine at 3AM?
What about 5AM?

What was the weather like? Vortecs have a known problem with old age and humidity induced moisture in the distributor cap...

just giving a timeframe.
it was actually raining hard that morning, so ill check there too, thanks

 

[Schurkey]

I have heard--but not verified--that pulling the #3 plug wire on a Vortec engine distributor cap can "fix" a non-starting condition.

Apparently, the insulation of the cap is weakest on/near the #3 conductor within the molded plastic of the cap. When the #3 plug wire is disconnected, the remaining 7 cylinders get spark and so the engine runs.

Fix is to replace the failed distributor cap; and, I suppose, to look for causes of excessively-high secondary voltage.