2015 chevy Silverado first start problem

[Cheech1419]

I have 2015 chevy 2500 with the 6.0L gas. The truck runs good but after sitting for a day it struggles to start. It's hard to explain. It has a good crank and tries to turn all the way over but struggles for about 5 seconds or less. I have no check engine light and no codes currently. Truck has 131000 miles. I'm at a lose and I'm thinking maybe a fuel issue but not sure. When I cycle the key before start you can hear the fuel pump turn on and off. 

 

After starting it, and the struggle, it runs like normal and if I drive it or just shut it off and start it again....it starts perfectly normal. Any help would be awesome.

 

Some codes I had before the issue was the Mass air flow sensor (replaced it) and an EVAP code (changed the fuel cap and the vapor canister solenoid)

[CamGTP]

Inspect and clean the throttle body, see if that does anything.

[rlcole321]

Also try cycling the key on and off a couple of times to "Prime" fuel pump (8 to 10 seconds between cycles), if this helps, then fuel pump is getting weak, and check valve not holding fuel in system, drain back issue.

[CamGTP]

The fuel pump only runs for 2 seconds on a "key on" just for reference. Per his post it seems he's already tried that. Fuel pressure test would be best if you think that is a cause.