The contact owns a 2017 Hyundai Tucson. The contact stated that several months after purchasing the vehicle, the vehicle was shaking abnormally while started. There was no warning light illuminated. The vehicle was taken to a dealer to be diagnosed. The contact was informed that there was an abnormal amount of carbon build up on the valves and the engine needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The approximate failure mileage was 90,000.