DRIVING ON HIGHWAY CHECK ENGINE LIGHT CAME ON REDUCED POWER LIGHT CAME ON, FEW SECONDS LATER ENGINE STALLED. PULLED TO SIDE OF ROAD, CALLED ON STAR SVC ADVISOR PERFORMED ONBOARD DIAGNOSTIC TEST, RESULTS INDICATED FAILURE IN THROTTLE SYSTEM/TRACTION CONTROL SYSTEM. ADVISOR ATTEMPTED FIELD REPAIR CYCLING IGNITION SWITCH 3 TIMES AND I ATTEMPTED TO START ENGINE. IT WOULD NOT START. BURNING SMELL COMING FROM VEHICLE, OPENED HOOD- AIR BOX SMOKING. INFORMED ON STAR I AM DISCONNECTING BATTERY. ON STAR ADVISOR CALL ON MY CELL PHONE, AND TOLD ME TOW TRUCK WAS COMING. WHILE AWAITING TOW TRUCK SMOKE BECAME MORE INTENSE FROM AIR FILTER. OPENED THE AIR BOX AND FOUND MASS AIR FLOW CENTER BURNING. REMOVED AIR FILTER AND DISCOUNTED DUCT WORK TO PREVENT FIRE FROM SPREADING. VEHICLE WAS TOWED TO LOCAL DEALERSHIP. SERVICE DEPT. WAS CLOSED AND SALESMAN OPEN SHOP TO ALLOW CAR TO BE STORED INSIDE. EXCHANGED PHONE NUMBERS. RECEIVED CALL 4/2/07 AND WAS ADVISED FOREIGN OBJECT (POSSIBLY A CIGARETTE) WAS INGESTED INTO FILTER WHICH CAUSED FIRE. AT THE SUGGESTION OF THE SERVICE MANAGER I CONTACTED MY INSURANCE AGENT SINCE I WAS TOLD THIS WAS NOT A WARRANTY ISSUE. AFTER INSPECTION BY MY INSURANCE CO. WHO CONSULTED WITH A FIRE INVESTIGATION/ADJUSTER, IN HIS EXPERT OPINION, THE FIRE BEGAN AT THE MASS AIR FLOW SENSOR AND WORKED IT'S WAY OUT. THE INVESTIGATOR FEELS IT IS IMPOSSIBLE FOR A CIGARETTE TO BE THROWN FROM A MOVING VEHICLE, REMAIN LIT, AND WORKS IT'S WAY UP A 2.5" OPENING INSIDE A FENDER OF A M