Car shus off when reaches operating temperature?

Hello, there could be any number of reasons the engine is shutting down when its hot out. It can be a sensor failing when hot, what is more likely is a cracked solder joint in one of the modules in the vehicle. A cracked solder joint will open up when hot and then close back up when it cools off. The difficult part will be determining what module is causing the stall out. When it wont restart, if you turn the key to the On position, do you see a Check Engine Light on the instrument cluster? It should come on for at least a few seconds. If its not, then the engine computer is not powering up. Since this is an intermittent issue, happening only on really hot days, this will be an issue that a technician/mechanic will need to catch when its happening, or duplicate the concern. There is most likely going to be a code stored in the engine computer due to the fault, so you can start with taking the car to a local auto parts store (AutoZone, advance auto, etc.,) and have them scan the vehicle for any DTCs (diagnostic trouble codes). If any are found, write them down so we know what you're dealing with, and we can go from there.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing