This week on Car Talk, one of our most memorable listener letters adds a third dimension. The "Andy Letter" asked whether two people who don't know what they're talking about know more or less than one person who doesn't know what he's talking about. Now, we're adding a third know-nothing to the mix. Does the "veritable pas de deux of breathtaking speculation" increase exponentially? Later, our Call of the Week features Stefan, who's wondering if it's time to let go of Grandma's '90 Olds Cutlass. His wife calls it the "ca ca" car, so we know where she stands, but are Tom and Ray ready to send it to the crusher? On Stump the Chumps, find out whether we correctly diagnosed a case of "cardboard fuel pump" syndrome. And, wondering what to do with your hands during a long drive? We've got some actual useful advice. All this, a new puzzler, and lots more, this week on Car Talk.