It does sound like a fuel problem. Could be the fuel pressure regulator or vacuum valve controlling it is bad, this would allow vapor lock. So check on that. Also pull your plugs and see what they look like at the face. there is a possibility that your ignition coil is failing as well. the hotter the engine or surrounding temperature are the weaker the spark get on a bad coil. Just a start and let us know how you are progressing. Good Luck