Why won't my car stay running?

On one of the hottest day this summer it started getting hot while idling. When we were going down the road it would cool down. We took it straight home. The next day we drove it 25 miles and shopped and on our way back it acted like it was running out of gas(10 miles in) but it had 1/4 a tank left. We couldn't get it to stay running. We put about a nother 1/4 a tank in of gas and then it started up and went probably 30 feet and died again. We finally got it to run for 14 more mile then it died and we couldn't keep it running. We've changed the fuel filter, fuel pump, and drained the gas from the tank because it didn't look right. Now we can get it to idle but everytime we push the gas to rev it up it dies and won't start unitl you let it sit for a little bit.