This week on The Best of Car Talk, is Martha's Passat shifting rough because of a failing transmission, or Martha's bad driving habits? The Car Talk Leadfoot Personality Test may give the answer. Elsewhere, Martin's brilliant roadside fix for his loose muffler could wind up setting the entire Northeast on fire; Dick's car is blowing so much smoke he's on Pennsylvania's Most Wanted Polluters list; and, Elizabeth is wondering if she should let a sleeping nail lie, in her tire. Also, can Tom and Ray teach Beth how to parallel park without being able to see what's behind her? All this and more, this week on The Best of Car Talk.