This week on Car Talk, while Mom is away, her kids will... hold a peeing contest on her Mercury Villager? That's what Sarah from New Jersey thinks happened when she took a weekend off and came back to a nauseating new aroma in her car. Will the Car Talk Olfactory Forensics Unit get the kids off the hook? Elsewhere on the home front, Barry and his wife are arguing over whether his lead foot is the cause of the bug convention taking place on his windshield, and Ronnie and her husband need refereeing over whether buying a black car in Florida is going to lead to flambeed tuchuses. Meanwhile, if you're looking for some actual car problems, Sandy's got a muffler-like noise that isn't coming from her muffler, and Michrie's DIY engine rebuild may have caused a DIY valve leak. And, did you hear the one about the parrot and the magician? All this and more, on this week's encore edition of Car Talk.