USUALLY I WILL START MY CAR AND START ROLLING OUT OF A PARKING LOT. ALWAYS BEFORE I CAN GET OUT OF THE PARKING LOT AND GET UP TO SPEED (USUALLY UNDER 20MPH AND 1500-2000RPM), I GET A SHORT (1-2 SECOND) LOUD AND STRONG VIBRATION THAT I CAN FEEL FROM THE GAS PEDAL. *GAS *JS