Ihave a 2004 530i. When I start the car in the morning the engine is very rough and makes an ungodly noise for 10-20 seconds or so. Other than that the car runs perfectly. After keeping the car for 3 days the dealer says its fine and I can come pick it up. WTF how can this be normal. It didnt do it when I purchased the car.

I just had this fixed on my '05. The dealer said the "Crankcase Vent Valves Leaking", "Replaced Crankcase Vent Valves".

Hope that helps.