DRIVING 2008 SUBARU FORESTER LL BEAN PULLING INTO PARKING PARK. VEHICLE STARTED RUNNING ROUGH, PARKED, ENGINE STOPPED RUNNING. ATTEMPTED TO RESTART SOUNDED LIKE A LOW BATTERY TURNED OFF ALL ELECTRICAL DEVICES ATTEMPTED TO START AGAIN, ENGINE STARTED RAN NORMALLY NO CAUTION LIGHTS. STARTED TO DRIVE HOME, ENTERED THE ON RAMP OF HIGHWAY. NOTICED WHITE SMOKE IN REVIEW MIRROR PULLED OFF OF HIGHWAY STOPPED VEHICLE TURNED OFF, SMOKE COMING FROM ENGINE COMPARTMENT SAW FLAMES UNDER CAR CALLED 911 FIRE DEPARTMENT. FIRE DEPARTMENT ARRIVED EXTINGUISHED FIRE.