Lexus sc400 shuts down



I have a lexus sc400, which when I leave the car outside under direct sunlight oe than 2-3 hours, it has a problem. The problem is that the car starts but it will turns off right away. The car RPM goes down from 1 to 0 and the engine shuts down.

I have change the motor relay and still have the same problem.

Does anyone know anything about this problem? Please help me.

Thank you