I bought an R56 about a month ago, 1.6 Cooper S, nice little car in good condition or so I thought. Last night, it started stuttering/jerking as I was driving, then the CEL came on yellow. I pulled over, not wanting to damage the car any further. Called a tow truck and waited about one and half hours. We were just sat in the car, with the key in the ignition, no lights/no music and I tried to start it back up after an hour, nothing, all lights just flickering and no turnover at all.

When the recovery turned up, they boosted the battery and I managed to start it with the same jerking/stuttering when trying to move the car. I checked the code when I got it home and it’s just reading as a P0302 - Misfire in Cylinder 2.

My question is, has anyone experienced anything similar before and if so, what happened? I’m not sure if it’s a faulty spark plug, coil pack etc. Or something more major like HPFP. The weird thing is the dead battery. I can’t tell if that’s been caused by whatever the problem is, or if that’s causing the problem? I did notice over the past couple weeks if I accelerated hard, it would jerk/stutter briefly, so I’m assuming it’s whatever was causing that has now completely failed.

Any advice would be greatly appreciated!