The contact owns a 2017 Ford Focus. The contact stated while driving approximately 20 MPH, while the accelerator pedal was depressed, the vehicle lost automotive power and shuddered abnormally. There was no warning light illuminated. The contact stated that the failure had occurred on several occasions. The vehicle was taken to a dealer where it was diagnosed that the there was an unknown part in the fuel tank that needed to be replaced. The vehicle was not repaired; however, the failure persisted. The manufacturer was notified of the failure. The failure mileage was approximately 90,000.