99 Civic si b16a2 with a P30 running on OBD1 with some bolt0ons. inatake headers etc.

I was wondering what could be the problem that when its really hot outside the car has a hard time starting but when its in the shade or its not too hot outside it starts up fine, i live in 100+ degree weather in AZ. when the car is in the shade and i start it it will start and catch idle after a bit but when its in the sun itll start and just turn off. idle wont catch. kinda weird if you ask me.