Hi Malcolm,

That points to an issue/leak in the turbocharging system that is allowing oil - or an oil mist - into the intake after the engine is turned off. This causes the engine to continue to run, but it has a built-in mechanism to stop it running out of control. It's likely that the car is also running with visible smoke at other times. Either way, we advise you get the car looked at by a good mechanic as soon as possible.