A control system for a vehicle engine coupled with an automatic transmission, which comprises a controller operative to control a controllable subject, such as ignition timing, in the vehicle engine, in accordance with a controlled variable determined for the controllable subject, for varying an engine output of the vehicle engine in response to an operating condition of the vehicle engine and further for reducing the engine output so as to suppress torque shock resulting from a speed change operation carried out in the automatic transmission, a controlled variable setting device for determining the controlled variable in accordance with the operating condition of the vehicle engine and an operating condition of the automatic transmission, and a controlled variable revising device for varying the controlled variable so as to restrict variation in the controllable subject when the speed change operation is carried out in the automatic transmission under a condition in which the controllable subject is controlled to reduce the engine output in response to the operating condition of the vehicle engine.