Abstract: To provide for smooth operation of a fuel injected engine, typically a diesel engine, if the diesel engine is controlled to reduce speed and towards idling thereof, it is first determined if the actual speed (n) of the engine drops below a certain speed threshold (NS), the commanded speed (N), upon such sensed occurrence is evaluated and the time rate (1/K) of an exponential function of commanded rate of drop in engine speed is changed as a function of the decrease (dn/dt) of the actual speed of the engine. Engine temperature can be used to modify the speed threshold, and the rate of change can, additionally, be evaluated with respect to a predetermined rate of change of speed of the engine. A difference between commanded and actual speed, applied to a proportional-integral controller can be used with an offset which offset becomes effective only upon rise of engine speed after a prior drop.