94 PA Ultra Supercharged dies after warm

[funkist1]

I have replaced the crank pos. sensor - Car ran great - gas mileage went from 20 mpg to 28 mpg!. After 1000 miles the trouble started again (dies after the engine warms up) I put in another crank pos. sensor ( more expensive one this time.. ran great - gas mileage went down to 25 mpg and lasted about another 1000 miles. Now it stalls whenever the engine gets warm. I live in Phoenix so it's hot here. The car has only 70k miles on it. It frightens my wife to drive the car when it's like this.
Any advice would be greatly appreciated. Thank you

[HotZ28]

What about the ICM, it can be heat sensitive also.

[funkist1]

I haven't tried that yet. I did put in a GM crank sensor but that didn't change it. I think before when it worked great for about 1000 miles it could have been that the weather was cooler. Now that it's over 105 every day it's stalls much more often. When it stalls, it starts right away and runs sometimes up to 20 miles before it acts up again. It is definitely much better in the early morning before it goes over 95 degrees. I really appreciate your input.