Went with my dad to buy a brand new 2000 F-150 V6. The salesman said "this new line of engines is so advanced, they don't even need sparkplugs" (he was referring to gas, not diesel). I told him I'd bet him the value of the truck that they did have spark plugs. Face-saving BS ensued.
It seems that very few salsemen know anything about the cars they're selling. If you read one article on the car, or even the brochure in the showroom, you probably know more about the car than the salesman.