gas smell in oil

You probably have a leaking injector. This is not because the engine is running too rich or you have poor combustion, there's a leak. Get it checked out ASAP, fuel in the oil can cause an explosion or fire at worst, and engine damage at the least so it's not something to ignore. Here's a directory link for you: http://repairpal.com/bmw-repair-in-fond-du-lac-wisconsin