NASCAR Contenders Aim to Avoid Mistakes (AP) AP - No more mulligans. When Nextel Cup leader Kurt Busch was hit by engine failure at Atlanta Motor Speedway and finished 42nd last Sunday, the mishap tightened NASCAR's new 10-race championship format. It also meant each of the 10 drivers in the title chase has had at least one finish of 30th or worse in the first seven events.