The copy I found of "Just a Real Good Car" is only three minutes long...as was the runtime listed on IMDB. However, I really suspect that the original film was much longer and the version I saw was truncated.
The story is scant. Charley (Charley Chase) has been asked to drive some neighbors to a picnic and once they are there, these folks behave obnoxiously and treat Charley like dirt.
There really isn't much more to it than this and the film is not particularly good because there just isn't enough plot to make it interesting.
No one is this obnoxious