OWNER HAD THE CATALYTIC CONVERTERS AND OXYGEN SENSORS REPLACED. A FEW WEEKS LATER, OWNER WAS DRIVING THE VEHICLE AND THEN STOPPED AND WAS SITTING IN HER DRIVEWAY USING HER CELL PHONE WHEN SHE SMELLED SMOKE. SHE GOT OUT OF THE VEHICLE AND LOOKED AT THE ENGINE AND SAW FIRE. EXHAUST SYSTEM HAD OVERHEATED, CAUSING MELTING OF THE EXHAUST HEAT SHIELD AND MATERIALS ON THE FLOOR PAN JUST ABOVE THE CATALYTIC CONVERTERS.