How to troubleshoot rough idling in a BMW 3 Series?

My BMW 3 Series has been experiencing rough idling recently. What could be causing this and what steps can I take to fix it?

First, check the air filter to see if it needs to be replaced. A clogged air filter can cause rough idling. If that's not the issue, then it could be a problem with the spark plugs or ignition system. I recommend getting a diagnostic test done to pinpoint the exact issue.

Have you recently changed your oil? Dirty oil can also cause rough idling. I suggest getting an oil change and see if that helps. If not, then it could be something with the fuel system. Get a fuel pressure test to see if that's the issue.

From my experience, rough idling can also be caused by a faulty oxygen sensor. I would recommend getting that checked and replaced if necessary. Also, make sure all the vacuum hoses are properly connected.