Legal Question in Criminal Law in Florida

It depends. The simple act of having sex in a car would not be illegal. However if the act is happening in public then it could be in violation of a number of laws.

There is nothing inherently illegal about having sex in a car, but with everything it depends on the circumstances. It absolutely is illegal to have sex while driving a car or otherwise while in public. But it is totally legal to have sex in a car if it is on your own private property (like in a garage) and not able to be seen by any member of the public.