I WAS RECENTLY IN AN ACCIDENT AT A STOPLIGHT. WHEN I ARRIVED AT THE STOPLIGHT SOMETHING FELL OUT OF PASSENGER SEAT ONTO FLOOR. I PUT THE TRUCK IN PARK, TOOK OFF MY SEATBELT, LEANED OVER TO PICK UP ITEM AND PUT IT BACK ON THE SEAT. I THEN PUT SEATBELT BACK ON AND PUT FOOT ON BRAKE AND PUT THE TRUCK INTO DRIVE. IT ALL HAPPENED PRETTY QUICKLY AND CAN'T SWEAR TO THE SPECIFICS BUT I THINK THE TRUCK MAY HAVE "JUMPED" A LITTLE WHEN I PUT THE TRUCK INTO DRIVE AND PROPELLED ME INTO THE CAR IN FRONT OF ME AT A VERY LOW SPEED. THE REASON WHY I BELIEVE THIS HAPPENED IS THAT I HAD PREVIOUSLY ASKED THE LOCAL GMC DEALER SERVICE CENTER IF THERE WERE ANY RECALLS OR OTHER REPORTS ON THIS TYPE OF THING HAPPENING BECAUSE IT HAPPENS WITH MY TRUCK. I HAD BEEN EXPERIENCING THIS "ENGINE JUMPING" UPON PUTTING IT INTO DRIVE ISSUE FOR SEVERAL MONTHS.