i replaced my alternator, water pump, and the belt (twice) it didnt change anything. this stuck me as odd since i have had my ur pulley for about 6 years and never had a problem. this problem started after i put a fresh set of belts on it. After further diagnoses i found that the belts had actually worn away the aluminum on the pulley and by putting new belts on, the pulley was only grabbing the very tip of the belt. i now have a whole new set of pulleys on order. look at your ur pulley very close and make sure there is not a notch on the downslope of each ridge.