The passenger car drivers want in general to feel good driveability, but they sometimes feel uncomfortable by shock and jerk phenomenon when they push or release acceleration pedal with clutch engaged. In this paper, the shock and jerk characteristics are studied on the vehicles of the throttle-by-wire system. With this system, the throttle is not directly controlled by drivers but via a microprocessor. So the control logic of the throttle is very important on tip-in and tip-out driveability. Experiments were carried out on two vehicles which show different control characteristics. The torque control logics were analyzed by measuring cylinder pressures. The results show that special torque control logic is needed at tip-in/out state for good driveability.