A hybrid electric vehicle includes an internal combustion engine configured to provide power to traction wheels, and a controller. The controller is configured to, in response to the engine being off and a power request exceeding an engine-start threshold, delay an engine start when vehicle speed is below a predetermined value. Delaying an engine start may include providing an engine-start-threshold offset. The offset decreases as vehicle speed increases. The engine is started when the power request exceeds a sum of the engine-start threshold and the engine-start-threshold offset.