Damn #@%&^$ car keeps dying!

I have a 1994 Olds Cutlass Ciera S with a 3.1L V6, with 127,000 miles on it. There's a problem with this car which keeps on creeping up whenever it gets hot outside. Every time I go uphill, the car stalls out. I'll pull over, wait about 15-20 seconds, then start it up again. I'll drive it for a bit, then at the next uphill it'll stall out again. And over and over. And here in Central Massachusetts there's certainly no lack of hills! Funny thing, it generally happens only when the weather outside is hot, on a mild or cool day or night it doesn't stall out - as a matter of fact it runs just fine. Could anyone hazard a guess as to what could be causing this? I just don't have the money to be spending hundreds of dollars at a garage trying to diagnose this problem.

Sounds a possible fuel pump problem get the pressure checked under load, need 37 psi.