All right, since my last case was a sucess, I decided to throw this one out there, too.
Years ago, me and a teacher were discussing horror when he brought up a movie in which Mark Hamill played a psycho. Specifically, he mentioned a scene in which Mark is riding in a Station Wagon before proceeding to stab the driver in the eye with a pencil.
After doing a little searching, I'm pretty sure it's "Midnight Ride" but I'd like someone to confirm this.
I am 99% sure that this is the movie you're looking for.
All right. I'll see if I can't track down a copy of that.