Can anybody help with my vivaro? It cuts out for no apparent reason when I press the clutch in if I'm approaching a junction, roundabout etc. It is then difficult to restart on the starter motor, but fires up easily if I can bump it. At all other times it runs like a dream with plenty of power. Sometimes the only way I can restart it is if I bump start it using the starter motor to give it enough momentum to get the engine tuning.