My 2004 pontiac grand am keeps stalling on very hot days.?

when it gets hot out after driving awhile all of a sudden the idle drops and starts to lug, if I give it any gas it will stall immediately, if i put it into neutral and dont touch the gas and let it just chug a little after about 1-2 minutes all of a sudden it will "catch" and the idle goes up to smooth and normal and i can drive off. If it stalls it wont start up for usually at least 5 minutes. Most does this in the city. on the highway its much better, but it stalls almost every time on my way ho,e as soon as i crest the mountain and start going downhill. It did this last summer as well and did not do it once over the winter. After it stalls the first time, and i get it running again my cruise control wont work at all, even when im on the highway running good. not until i let it sit for a few hours will the cruise work. I have checked at the schraeder valve on the fuel rail when thiis happens and it seems to have good pressure still. If anyone can help I would really appreciate it! thank you... btw it has a 3400 v6 and is a automatic. car does not seem to overheat when this happens, its usually tight around the middle of the gauge. It feel alot like a vapor lock of the old days, only I rhoufhr fuel injected engines cant vapor lock...tjamls again.