Abstract: A vehicle engine has a throttle stop positionable in response to an actuator command signal to determine engine idle speed. Apparatus is provided to generate a speed error signal having both an absolute value and a further characteristic indicative of high or low speed; and further apparatus is provided including a memory effective to store actuator command signals corresponding to specific speed error signals and speed correction apparatus effective to obtain an actuator command signal from the memory corresponding to each speed error signal and supply the actuator command signal to the throttle stop positioning apparatus to correct engine idle speed in the direction of a predetermined desired engine idle speed.