The contact owns a 2016 Ford Explorer. The contact stated that while driving approximately 65-70 mph, there was an abnormal exhaust odor entering the vehicle. When the accelerator pedal was released, the odor dissipated. There were no warning indicator lights illuminated. The driver and passenger sustained a headache due to the odor but medical attention was not provided. The vehicle was taken to an independent mechanic who stated that the seal was broken. Additionally, the mechanic informed her to use premium or Chevron fuel. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was contacted, who opened a case, and referred her to the NHTSA hotline. The failure mileage was approximately 112,000.