Engine Stalling

I have an 85 SS. It runs good, but lately it has been stalling after I drive it for a while. After about 30-45 mintes of driving, it begins to act as if it is running out of gas. I push the gas pedal down, but it doesn't seem to be getting any fuel. Sometimes it will die out, but cranks right back up--even drive's a little ways without messing up. If I let off the gas or sit idle, it seems to have no problem. I changed the fuel filter first, which didn't fix the problem. So next I replaced the ignition module and condenser/capacitor. Still not fixed. So then I changed the map sensor, and still nothing.
The car runs fine and does not always mess up. It seems like something is getting hot, and when it does it starts messing up. It also acts like some kind of electrical short. I had a similar problem in a 94 Mustang I used to own, and it turned out to be the distributor. What other things could cause the car to do this?

have you thought about the lockup solenoid? it wont let it downshift and will keep the car stuck in lockup, hence the killing of the motor. look it up on google. that is the prime problems with our montes. it is like a 30 dollar part and might as well change the tranny filter and fluid while under there. if that dont fix it, call a mechanic!!! haha..im sure that will fix it