JAGUAR, XJ8L, 2000 MODEL; VEHICLE WILL ACCELERATE ON ITS OWN. WHILE IN REVERSE VEHICLE ACCELERATED, CONSUMER WAS UNABLE TO STOP VEHICLE AND IT ENDED UP HITTING TWO OTHER VEHICLES. VEHICLE HAS ACCELERATED 12 TIMES IN STOP AND GO TRAFFIC, RPMS WENT UP AND ENGINE REVVED. DEALER CAN NOT FIND CAUSE. *AK *TT