Tl* the contact owns a 2012 gmc sierra 1500. while driving approximately 50 mph, the vehicle hesitated. the contact drove the vehicle to the dealer thinking that it needed a tune up. the dealer diagnosed that the camshaft and uplifters needed replacement. the vehicle was not repaired. the manufacturer was notified of the failure. the approximate failure mileage was 140,000. .....updated 08/11/16 *bf the consumer also stated there was an issue with transmission. updated 08/17/16 *jb