Engine control method for ensuring rapid initiation of treatment of exhaust gas

Disclosed is an engine control method for a vehicle having an electronically controlled drive line such as an electronic multi-speed transmission with an automatic gear box. The method of operation comprises the steps of turning on the engine and then keeping the engine revs high whilst an engine is idling and not connected to a transmission system, for instance whilst the neutral position is selected. The high idle speed is maintained on sensing that the gear select is moved from neutral to drive and the controller delays dropping the engine idle speed and engaging the drive line until the wheel brake is removed. Sensors may be provided to detect release of the wheel brakes and gear position. The method is used to provide a high engine operating speed on engine start up and/or warm up to ensure that the engine heats up rapidly so that the hot exhaust fumes can be used to heat a catalytic convertor to bring it to its active operating temperature.