BMW Questions? Ask a BMW Repair Expert for Answers.
Hello, I'm Brandon - BMW tech.
The air fuel ratio is running rich. The fuel injector can be leaking, the air filter could be clogged and the oxygen sensors could be bad.
Typically it is the oxygen sensor 's function to adjust the air fuel ratio.
What kind of oil weight are you using?
This engine called for Synthetic Oil 5w-30. Is there reason you are putting 10w-40? The oil is thick.