WHEN SLOWING DOWN AT TRAFFIC LIGHT CAR HESITATED AND THEN JERKED FOWARD, AS IF I HAD BEEN HIT FROM BEHIND. IT WAS ENOUGH TO MAKE MY BACK AND NECK SORE. I TOUCHED THE ACCELERATOR PEDAL TO GIVE THE CAR SOME GAS AND THE ENGINE FREELY REVVED, EVEN THOUGHT THE TRANSMISSION INDICATED IT WAS IN 'DRIVE'. THE CAR HAS DEVELOPED A HESITATION TO ACCELRATE BEFORE THE INCIDENT, AND AFTER. THE CAR HAS ALSO BEEN SHOWING SIGNS OF EXCESSIVE FUEL CONSUMPTION.*AK