I HAVE LOVED MY 2011 TOYOTA SIENNA FOR 5-6 MOS. NOW. UPON BACKING UP IN MY FLAT DRIVEWAY AREA ON 10/24/11, AT A SLOW RATE TYPICAL TO BACKING UP IN A DRIVEWAY, I FOUND MY VAN PROPELLING VERY FAST STRAIGHT BACK/IN REVERSE. THIS TOOK THE VEHICLE DOWN OVER A SLIGHT HILL OF OUR YARD INTO A LARGE PINE TREE. THE THICK SPRUCE TREE HAS A HUGE HOLE/OPENING/DAMAGED AREA AND MY ENTIRE BACK OF THE VAN IS VERY DAMAGED, ENTIRE REAR WINDOW BUSTED INTO HUNDREDS OF SMALLER PIECES, ITEMS IN THE CAR PROJECTED ONTO THE GROUND BEHIND US. THE LIFTGATE, REAR WINDOW AND BUMPER ARE VERY CAVED IN AND DAMAGED. I CAN ONLY DESCRIBE THIS AS SECONDS OF TOTAL CONFUSION, SPEED, LACK OF CONTROL, SHOCK. I'M FEELING LIKE THE VAN IS "POSSESSED", AND I WILL NOT DRIVE IT AT ALL AGAIN. I DID NOT WITNESS ANY INDICATORS OF ANY ACCELERATOR ISSUES IN THE 5-6 MOS. I'VE OWNED IT. I WOULD BE LYING IF I SAID I WAS POSITIVE I WAS STILL BACKING UP OR IF I WAS IN THE PROCESS OF PREPARING TO BRAKE AND SHIFT INTO DRIVE TO PULL FORWARD AND OUT OF MY DRIVEWAY. THIS HAPPENED SO QUICKLY FOR DOING SOMETHING AT SUCH A VERY SLOW REVERSE SPEED, THAT THE DETAILS IN THAT SECOND IT ALL CHANGED AND ACCELERATED, I CAN NOT SAY FOR SURE WHAT SPECIFICS WERE BEING DONE AT THAT VERY MOMENT OF DRASTIC CHANGE IN SPEED. I'VE ALWAYS LOVED TOYOTAS. WE'VE HAD A FEW NOW. THIS IS THE LAST ONE I WILL BUY BECAUSE I JUST CAN NOT EXPLAIN WHY OR WHAT OCCURRED TO MAKE IT GO FROM SINGLE DIGITS IN REVERSE TO VERY QUICKLY SPEEDING IN REVERSE. I'M TAL