TL*THE CONTACT OWNS A 2001 FORD EXPEDITION. WHILE DRIVING 55 MPH, THE CONTACT HEARD A LOUD POP AND THE VEHICLE BEGAN RUNNING VERY ROUGHLY. SHE PULLED TO THE SIDE OF THE ROAD AND SMELLED GASOLINE FUMES COMING FROM THE VEHICLE. AN INDEPENDENT MECHANIC CONFIRMED THAT THE NUMBER 3 SPARK PLUG HAD EJECTED FROM THE VEHICLE, AND ONLY 7 OF THE 8 SPARK PLUGS REMAINED. HE ALSO WARNED THAT THERE WAS A POTENTIAL RISK OF A FIRE IF SHE PROCEEDED TO DRIVE THE VEHICLE IN THAT CONDITION. THE VIN WAS UNKNOWN. THE FAILURE AND CURRENT MILEAGES WERE LESS THAN 100,000.