Got Oil Changed, oil cap was left loose...now car is running rough

[Haulin1333]

I got a oil change and they left the oil cap loose. Car was running really rough. Was throwing misfire codes, didnt relize oil cap was loose. Lost about 1 quart of oil. So tightened the oil cap and it's running a lot better, but still a little rough. Could it have damaged something? 2008 328xi

[jclausen]

No it created a huge vacuum leak because all the air the comes to the engine is measured thru the air mass sensor and is called metered air any air leak after that is called unmetered air and the computer and the car does not like unmetered air. So when the oil cap was missing that was a huge vacuum leak(unmetered air) and the engine ran rough. Hopefully with he oil cap missing it didn't make a mess of the engine, if it did they need to steam clean the engine for you and who did this oil change?

[Haulin1333]

It didnt make much of a mess becuz oil cap wasnt completely off, just kinda ran down the side.

But car is still idling rough, going down the road it is fine. But it's only idling at about 600rpms, which is a little low. Which is causing it to idle rough.