THE SIERRA SURGES FROM PARK TO REVERSE AND DRIVE. I BUMPED A VEHICLE TODAY, AND THE SURGE HAS BECOME AN ISSUE THIS WEEK AND THERE IS NOT EVEN 9,000 MILES ON THE TRUCK. THE AFM IS ROUGH SHIFTING BETWEEN V8 AND V4 MODE TOO. NONE OF THIS WAS AN ISSUE UNTIL RECENTLY. MY SPEAKERS ALSO VIBRATE LIKE A BLOWN SPEAKER ON HIGH DEFINITION RADIO, BUT NOT ON REGULAR RADIO STATIONS.