98 3.4L not getting fuel

I have just had the motor replaced in my 98 tacoma. It's a 3.4L. I changed the fuel filter before running it. It have driven it 265 miles since the engine install. It has started and ran like a new one. Yesterday I was running errands around town turning the truck off and back on at each stop. I pulled it in my driveway and killed it. I went back out 15 minutes later and it wouldn't start. It sounded like it was starving for fuel. I left it alone for about 3 hours, turned the key and it cranked right up.

Any idea what this could be?