Method and arrangement for providing a vehicle having a combustion engine (1) with valves (7, 8) adapted to have variable valve timing and/or valve lift height. The valves are provided with operating devices (9,10) that are controlled by electronic controlling devices (3), which are arranged, while the vehicle is being driven, with the aid of entered information about at least the gradient of the road and the throttle position, to calculate future resistance to forward motion and the period of time to a future transient in the engine's operating condition, for example in association with a future change of engine operating mode and/or a future gear change in a gearbox (2) connected to the engine. The controlling devices are arranged to control valve timing and/or the valve lift height during the period of time for optimization of the engine's performance, once the transient has arisen.