A method for controlling an engine using a continuously variable transmission, the method decreases the fuel consumption of the engine in a transient shifting condition. When the operator displaces the accelerator means and the magnitude of the difference between a steady state engine speed, which corresponds to the amount the throttle means of the engine is opened, and a previously detected engine speed differs from a predetermined constant value, the engine speed abruptly increases after a predetermined time elapses and thereafter the engine speed gradually changes to the steady state engine speed. The abrupt increases in the engine speed is a function of a vehicle speed and the amount of the throttle opening.