Hot is a relative word in that your 5.0 engine will actually make less power when it is cold than when it is at proper operating tempature. Here is why: When you first start your car the engine is cold and therefore the computer runs in what is called "open loop" or said another way, the computer is dumping more fuel into the motor and making it run richer or less than optimal (14.7:1 A/F ratio). This is done to help the motor reach operating temp much quicker. Once the engine reaches operating temp. then the air/fuel ratio becomes more favorable for making power.
Although, I think your point may be that when it is very hot out (with a warmed up engine) your car feels like it has less power than when it is cooler (with a warmed up engine). Given this situation, yes, a warmer day will cut back on power due to the fact that the air is less dense and therefore contains less oxygen molecules per unit of air.
Hope this helps.
E
------------------
1991 5.0 LX Coupe - 38,000 miles
13.17 @ 106.14 mph w/ 2.138 60'
|