2001 Chevrolet Truck Extended Crank Time

I have a 2001 Chevrolet pickup with 5.3 V8 200,000 miles. When I have driven the vehicle and it sits for approximately 15 minutes you can crank for approximately 3-5 seconds without it starting, then try again and it cranks right up. If it sits for an hour or so or all night it starts like it should. I sent it to the local GM dealership and now have new fuel pump, fuel pressure regulator, and PCM and it still does it. They did figure out that my injectors are not powering up when it is not starting. It is getting fuel and fire but no life from the injectors. Has anyone else had this problem?

Sounds like you may have some leaky injectors which bleed off and flood the warm engine…With a gauge connected to the rail, you can watch the fuel pressure bleed off as the injectors drip into the engine. Have the shop take a second look…

Bad MAF will cause injectors not to pulse or a heat soaked crank sensor.

Can the MAF malfunction without throwing any codes because I have no codes.