HAD THIS PROBLEM WITH MY Q-2 AND IT SEEMED TO PROGRESIVELY WORSEN OVER TIME. ONE DAY I NOTICED THE CAM AND THE STRING WERE OUT OF ALIGNMENT. WHEN THIS OCCURS IT CAUSES PART OF THE CAM TO RUB ON THE CABLE SERVING. I CALLED MATHEWS AND THE TECH HAD ME MEASURE THE BRACE HEIGHT AND AXLE TO AXLE LENGTH..BOTH OF THESE WERE OUT OF FACTORY SPECS AND HE ADVISED I HAD TO TWIST UP THE STRING TO CORRECT THEM. ONCE THIS WAS CORRECTED I HAV'E'NT HAD A PROBLEM.