The contact owns a 2021 GMC Yukon XL. The contact stated while driving 80 MPH, the engine was running unusually rough, and there were several unknown warning lights illuminated. The vehicle was taken to an independent mechanic and was diagnosed with a fractured valve push down lifter. The contact was informed that the valve push down lifter needed to be replaced. The vehicle was not repaired. The contact was advised to take the vehicle to the dealer for assistance. The vehicle was towed to the dealer where it was diagnosed with a fractured valve push down lifter and a failed cam shaft. The contact was informed that the valve push down lifter and the cam shaft needed to be replaced. The vehicle was repaired. The manufacturer was made aware of the failure but provided no assistance. The contact referenced an unknown recall repair, which had a similar failure description, however the VIN was not associated with the recall. The contact was advised to contact the NHTSA Hotline to report the failure. The failure mileage was approximately 109,000.