You ask a couple different questions and it isn’t clear if you are asking about efficiency or what.
Yes, gas will evaporate more the hotter it is.
The reaction rate of gasoline combustion does increase when the temperature is higher, so all other things being equal it would burn faster.
What does that mean for a car? There will be somewhat less power because as others have mentioned, the hotter the air is the less dense it is and the less oxygen gets into the cylinders.
Your overall gas mileage can increase though because your car experiences less air resistance.
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