Fuel system problem?

Car starts and runs just fine, but after about 20 minutes of driving, it starts to stall like it's out of gas. Eventually it will die and won't start again. If I let it sit for awhile, it will start back up and run just fine for another 20 minutes or so. First I changed the filter, then the pump, then replaced all the rubber hoses. I even re-routed the hoses outside the engine bay in case the heat was causing the fuel to boil. My only guess left is the fuel tank, but before I drop it, I thought I'd ask someone smarter than I on this subject.

Thanks

That's what I was thinking when I re-routed the hoses. Is there anyway to clear the whole system out?

Interesting. I hadn't thought of the gas cap. I'll try it this weekend.