Abstract: An engine control system corrects an air-fuel ratio of an air and fuel mixture during feedback control in a feedback region of engine operating conditions and during a learning control in a learning region of engine operating conditions. A purge region of engine operating conditions, in which purging of fuel vapor into the engine is conducted, is defined so as to have a portion overlapping with the learning control region. The air-fuel learning and the fuel vapor purging are conducted alternately. A specific region of engine operating conditions is defined in the purge region for higher flow rates of intake air. The control system undergoes the air-fuel learning prior to the fuel vapor purge when engine operating conditions are in this specific region.