DURING EXTREME COLD AMBIENT TEMPERATURES AND UNDER CERTAIN DRIVING CONDITIONS, MOISTURE IN THE CRANKCASE MAY ENTER THE PCV SYSTEM, FREEZE AND CAUSE PRESURE IN THE ENGINE CRANKCASE. THE PCV FITTING IN THE UPPER INTAKE MANIFOLD MAY FREEZE OR THE FRESH AIR LINE MAY BECOME BLOCKED. IT IS ALSO POSSIBLE, BUT LESS LIKELY, THAT ICE MAY BUILD UP ON THE THROTTLE PLATE OR THE THROTTLE BODY AND CAUSE THROTTLE STICKING. *TT