I have got a vw Golf 4 2004,while i was drving it suddenly lost power and i could hear the the vibration coming from the engine,when i stop the idling wa so bad and i could smell some of the unburnt petrol from the exhaust,i replaced all spark plugs and i checked each wire lead they all work(by pulling one by one while engine is running) what could it be?

Philani, July 2009