NAPA Auto Parts is leaving Michael Waltrip Racing after the team's attempt to manipulate a race to get Martin Truex Jr. into NASCAR's version of the playoffs.
Truex's primary sponsor was in the first year of a three-year extension announced last August. The deal ran through the 2015 season.
The company issued a harsh rebuke of MWR last week after NASCAR sanctioned the organization for its shenanigans in the Sept. 7 race at Richmond. MWR was punished for deliberately manipulating the outcome of the race in an attempt to get Truex into the 12-driver Chase for the Sprint Cup championship field.
NASCAR kicked Truex out of the Chase and conducted a larger investigation that uncovered at least one other case of race manipulation.