WHILE DRIVING MY 1999 FORD EXPEDITION 5.4L AND COASTING DOWN A HILL ALL OF A SUDDEN A LOUD POP AND THE A LOUD EXHAUST NOISE. I SMELLED FUEL AND IMMEDIATELY PULLED OVER. UPON OPENING MY HOOD I FOUND A SMALL FIRE (THANK GOD I CARRY A FIRE EXTINGUISHER) AND THAT MY ENGINE HAD SPIT OUT A SPARK PLUG STRIPPING ALL THE PLUG THREADS. IT IS NOW IN THE SHOP BEING REPAIRED FOR AN UNKNOWN COST. *TR