The Bobcats trailed by 14 points heading into the final period, but outscored the Pistons in that quarter 41-17.
Walker scored 34 points, three more than in any other game this season. He hit 12-of-17 from the floor and made all of his nine foul shots.
It was Charlotte's third straight victory.
Brandon Jennings scored 26 points and was one of six Detroit players in double figures. The fourth-quarter collapse led to Detroit's sixth loss in its last eight home games.
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