A vehicle having a vehicle body, a seat, an engine, a throttle body, a
throttle valve, a throttle valve actuator, a throttle operator, a
throttle operator position sensor, a cruise control switch, and a vehicle
speed sensor. An ECU controls operation of the engine in one of a normal
operation mode and a cruise control operation mode. When in the normal
operation mode, the ECU sends a first control signal to the throttle
valve actuator based on the throttle operator position signal. When the
cruise control switch engages the cruise control operation mode, the ECU
sends a second control signal to the throttle valve actuator based on the
vehicle speed signal such that the vehicle speed is maintained at a
vehicle cruising speed. The ECU returns to the normal operation mode when
the throttle operator position becomes less than or equal to a reference
throttle operator position.