Abstract: This invention adapts stored engine control parameters to variations in the air and fuel supply systems to improve open loop air fuel ratio control. An offset amount is calculated which is to be added to measured air flow in an internal combustion engine capable of operating in an open loop mode and a closed loop mode. In the method, an engine operating condition in a closed loop mode at idle is established. The current average fuel control signal is calculated. The current average fuel control signal is compared to a previous average open loop fuel control signal to obtain a difference average fuel control signal. An offset control signal is generated as a function of the difference average fuel control signal and is to be added to all future air flow measurements thereby providing for adaptive correction and more accurate air fuel ratio control in the open loop mode.