2003 Chevy Tahoe stalling out while driving

I have been having in issue for over a year now. The issue only happens when it is warm outside, the truck runs great in the winter.
The problem started while driving in rush hour traffic. The truck started to stall, pushing the gas pedal would not initially respond. The engine would finally respond after several seconds. Once the car cools down it runs fine. I have replace the fuel filter, 3 pumps ( last one was an AC Delco) relay switch fuel injectors cleaned and a new wiring harness.
I am at a loss at where to look next. Everyone says that it sounds like vapor lock, the only problem is that it is fuel injected.