Florida car may have several meaning including the ones listed above. Florida was known (well south fl anyway) as a giant retirement community, a huge misconception, but I guess for the people from other states who saw their grandparents moving to fl they figured, hey this state is full of old folks. Thus a Florida car which was driven only by an old lady, its engine has never been stressed, and possibly never driven that much. Also, Florida is a fairly flat state, no hill/mountains for the engine to strain on.
Those were my 2 cents on FL cars. (next Fl chicks..)