It was a movie in the early 80's that started live action went to cartoon for 90% of the movie and then ended live action. From what I can remember it was about a boy who got a toy car that took him to a cartoon fantasy land where he meets this cat that helps him to return home while teaching him a life lesson. I think the car was red and that they rode it through most of the movie.

Try, "The Phantom Tollbooth" (http://imdb.com/title/tt0064806/) (1970)