The contact owns a 2018 GMC Sierra 1500. The contact stated that while driving on the highway at various speeds, the vehicle occasionally shuts off. The contact stated that several unknown warning lights were illuminated. The contact stated that the vehicle was pulled over to the side of the road and restarted. The contact was able to continue driving. The vehicle was taken to a local dealer and was diagnosed; however, the cause of the failure was not found. The contact was informed to take the vehicle back to the dealer if the failure returned. The manufacturer was notified of the failure. The approximate failure mileage was 128,000.