Relive the ups and downs of this weekend's LifeLock 400 at Kansas Speedway by checking out this week's best pictures.

KANSAS CITY, Kansas (Ticker) - For all but a few drivers in Sunday's NASCAR Nextel Cup LifeLock 400 at Kansas Speedway it was not a good day to be in "The Chase."

Kyle Busch's Kansas Speedway misfortunes continued Sunday in the LifeLock 400 NASCAR Nextel Cup Series event. Busch won a close contest against Matt Kenseth in the Yellow Transportation 300 NASCAR Busch Series race on Saturday, only to have his No. 5 Chevrolet fail postrace inspection after NASCAR officials discovered an illegal intake manifold.

Kyle Busch, whose strong performances early in the Chase for the Nextel Cup put him among the serious title contenders, crashed early in Sunday's race at Kansas Speedway after Dale Earnhardt Jr. hit him from behind.

Championship contender Tony Stewart will not be penalized for cursing on live TV following practice at Kansas Speedway.

Kyle Busch, whose strong performances early in the Chase for the Nextel Cup put him among the serious title contenders, crashed early in Sunday's race at Kansas Speedway after Dale Earnhardt Jr. hit him from behind.