Mini One Engine Trouble

Sounds like a misfire. I had similar symptoms on my old Ford Focus – rough running, stalling, and the check engine light. Have you checked the spark plug and coil pack connections? Could be a simple fix.

When you say 'coil pack connections', what exactly should I be looking for? Anything specific?

Yeah, check for loose connections or damaged wires going to the coil pack. On the Focus, it was a cracked connector. Vehicle diagnostics should pinpoint which cylinder is misfiring. If it's that, replacing the coil pack is usually straightforward, but it's best to take it to a workshop if you aren't comfortable doing it yourself.

Just wanted to give an update. It was indeed a defective ignition coil. Turns out the cable or plug connection was faulty, just like I suspected. Cost me 95€ to get it sorted. Thanks for the help!