The contact owns a 2018 Ford F-150. The contact stated that upon starting the vehicle, there was an abnormal rattling sound coming from the engine. No warning light was illuminated. The contact stated that the failure had been recurring and had progressively worsened upon starting the vehicle. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The contact related the failure to Ford Campaign Number: 21N03. The manufacturer was contacted and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 60,000.