A method for controlling a hybrid electric vehicle includes selecting a first target engine speed in response to a driver power request, calculating an available engine torque at the first target engine speed, adjusting the target engine speed if the available engine torque is insufficient to satisfy the driver power request, and commanding an engine to run at the target engine speed. The first target engine speed is optimized for fuel economy. The calculated available engine torque is less than a calculated maximum engine torque at the target engine speed, such that a torque reserve is maintained for engine vacuum.