[puhahacj]

So I literally just passed 50k miles, exhausting the factory warranty in the process, and all of a sudden my '08 328i starts acting up! It idles pretty rough both in park or in drive, and it doesn't matter if it’s at start-up or after the engine’s been running for a while. I don't remember what RPM the car was idling at before, but it appears to be hovering between 500-600 now. I would describe the vibration from the engine bay as mellow to mildly violent, but it's constant whenever the RPM dips below a certain level (I want to say below 700?)

Anyway, I replaced the air filter (although it didn't look particularly dirty) and added some Lucas Fuel Treatment, hoping that these relatively inexpensive and simple fixes would do the trick. Not to my surprise, they didn't do a darn thing. So before I resort to my last option and take it to a mechanic, I figure I'd give Plan B a shot and reach out to my fellow bimmer enthusiasts for some advice. Does anyone think they might know what's going on? Any comments are greatly appreciated!