The contact owns a 2019 Hyundai Tucson. The contact stated that while driving at 5 MPH, the vehicle slowed down. There were no warning lights illuminated. The vehicle was taken to the local dealer, where it was diagnosed that the knock sensor needed to be replaced. The vehicle was repaired, but the failure recurred. While driving, a month later, the vehicle slowed down. The vehicle was taken back to the local dealer, where it was diagnosed that the knock sensor needed to be replaced. The vehicle was repaired, but the failure persisted. The vehicle was taken back to the local dealer, where it was diagnosed that the engine needed to be replaced. The engine was replaced. Additionally, while driving, an unknown vehicle crashed into the rear of the vehicle, and it continued to move forward. The steering wheel became stuck and was uncontrollable. The driver shifted the gears to park and neutral. The vehicle was idling high and low. The driver depressed the push-to-start button, but the vehicle continued to move and drove onto the lawn over a flower bed and fence, went across a two-way highway, slowed down, and stopped. The vehicle was towed to a body shop. A police report was filed. There were no reported injuries, fire, or air bag deployment. The manufacturer was contacted to obtain the EDR box, and they sent an engineer who reported that the air bags were not supposed to deploy and was unable to duplicate the failure. The failure mileage was approximately 1,000.