Fuel Delivery Problem??

I have an O1 Sierra 5.3 lit. here's the problem, its hard to start esp. when it sits for a while, engine cranks for several seconds before it starts. If I turn on the key in the on position for a second or two and then start it, it cranks right up, sounds like a fuel delivery problem to me. I changed the fuel filter and it did not help. I had the fuel pump replaced at about 30K under warranty but it stopped working all together, truck died on the fwy.

Where is the PVC valve on this engine?

Thanks for any input.