Joyride (1997)

To a dumpy motel in an out-of-the-way little town, a mysterious woman, calling herself only Ms. Smith, comes to stay. Not only is she stunningly lovely, but her big black convertible is a beaut. J.T., the just-out-of-high-school son of the motel's owner, is taken by the car, and in an attempt to liven up his dull life, and possibly to impress Tanya, a hotel guest who flirts with him and wants to be a model, he steals the car, and brings along Tanya and his pal James. What they don't know is that Ms. Smith is a professional killer, and J.T. thinks he can make things work to his advantage when the three of them find a corpse in the trunk of the stolen vehicle...