Why car dies in hot weather?

Wrought out radiator ,replace thermostat.

this could be seveal diff things seek diag and est from your mech. could be electrical or fuel related. does car over heat at all?

Try running a full tank of gas the fuel pumps are known to go out . if you run a full tank and it seems to help because its keeping it cooler then you know its time to replace the pump . It is never good to run a vehicle on below a quarter tank any make or model at that