I own a VW Golf MK IV and my problem is that the engine keeps cutting out when the car comes to a stand and the alternator light comes on. It also sometimes cuts out momentarily when turning a corner slowly (aspecially if you're holding the clutch down) only to start up again. The battery died recently and a breakdown service fitted a new one and the problem has only started since the new battery was installed. Also, looking in the service book I found that the last time the battery was changed the alternator belt was changed at the same time. Coincidence? The car has no trouble starting and there are no warning lights on when you turn on the ignition.