To reduce HC and CO emissions, the Throttle Positioner (TP) opens the throttle valve to slightly more than the idle position when decelerating. This keeps the air/fuel ratio from becoming excessively rich when the throttle valve is quickly closed. In addition, the TP is used to increase idle rpm when power steering fluid pressure exceeds a calibrated value and/or when a large electrical load is placed on the electrical system (headlights, rear defogger etc).