PURPOSE: To provide a system for controlling transient torque output of a multicylinder, variable displacement, spark-ignited, fuel injected automotive internal combustion engine during periods when the effective displacement of the engine is being changed.

CONSTITUTION: This system comprises a spark timing controller 14, a throttle controller 20 for positioning an intake throttle 22, and an engine cylinder operator 18 for deactivating and reactivating at least some of the engine's cylinders, and an engine controller has a microprocessor 10A for changing an ignition advance angle and controlling the amount of air entering an engine cylinder so that torque output of the engine remains unchanged during the transition from operation with a first number of operation cylinders to operation with a second number of operation cylinders. Consequently this system is provided with the engine controller which selects the number of cylinders to be operated and has the microprocessor 10A operating the spark timing controller 14, the throttle controller 20, and the engine cylinder operator 18.