FOR THE PAST YEAR OR MORE, DRIVING ANY DISTANCE STARTED FITS OF YAWNING. ON OCCASION IT HAS BEEN DIFFICULT TO STAY AWAKE. ON JULY 27, 2015 I APPARENTLY BLACKED OUT IN VERY HEAVY TRAFFIC AND WOKE UP HAVING COLLIDED WITH THE VEHICLE IN FRONT OF ME. DIAGNOSED AS PRE-DIABETIC, I BELIEVED THIS WAS MY PROBLEM, AND UNRELATED TO MY VEHICLE. HOWEVER, MY CAR TOOK 31 DAYS TO REPAIR, AND WHILE DRIVING THE RENTAL CAR THIS YAWNING NEVER AGAIN OCCURRED. YESTERDAY (SEPTEMBER 24, 2015) IT HAPPENED AGAIN. NO COLLISION, BUT GREAT DIFFICULTY GETTING HOME, EVEN WITH THE DRIVER'S WINDOW OPEN FOR MAXIMUM FRESH AIR. I AM CONVINCED THAT THE VEHICLE IS LEAKING CARBON MONOXIDE INTO THE PASSENGER CABIN. IT'S GOING BACK TO THE DEALER TODAY