My car keeps idling at 500 in drive on a hot day but when I turn the A/C on it idles at 750 like normal, cleaned my MAF and throttle body 2 times already and my air filter. Still have the same issue and was wondering is that normal because in FL it gets really hot outside and at night my car idles at 750 or 650.

 

Common issue. Use Google. Not sure if it's "normal" but I have never seen a conclusive fix.

 

The idle speed is determined by the ECU in response to whole raft of sensor measurements.
When you switch on the AC you add a 2Bhp load to the engine, so it increases the idle to compensate.
Personally I wouldn't worry about it. If it starts stumbling or misfiring, then you have an issue.

 

Believe it or not, mine stopped doing it after I got new engine mounts. They had to drop the subframe a bit... but didn't unplug anything.

A/C only adds load when the clutch is locked up. Leave the A/C on. Ain't hurting you to dehumidify the car.