Began having severe headaches,disoriented,sudden onset sleepiness. lack of judgment when riding over an hour in vehicle. mds said have it checked for co but gm buick could not find a problem, we took to dealer several times. hazmat person for state of va. calibrated and let us use his testing equipment,with findings positive for co=70.trade assist was negotiated but gm stated no co found. need sensor installed in vehicles or equipment to check for this interior deadly gas problem available at dealerships to check for this problem. i stopped riding in vehicle 7/2009. trade in/new vehicle picked up 1/15/10.gm had been notified of problem 4/09. no corrections made to vehicle. we were told to ride with the windows rolled down. *tr