BMW 6 Series Rough Idle & Stalling: Ignition Issues?

Hey there! I had nearly identical issues with my 2007 BMW 650i last year. The symptoms you're describing match my experience exactly, rough idle, stalling, and jerking during acceleration. Initially thought it was something major, but turned out the ignition coil packs were failing, and two spark plugs had completely worn out. The diagnostic showed misfiring in cylinders 3 and 6. This is actually a common issue in these engines when they reach this mileage range. At the garage, they found corroded connections on the coil packs, and there was visible damage to the spark plug cables. Once they replaced the coils and plugs, the engine ran smooth as new. It wasn't a serious repair in terms of engine damage, but definitely not something you want to ignore as it can lead to catalyst damage if left unchecked. One tip: make sure they check all coil packs, not just the failing ones. They tend to fail in sequence as they age. Hope this helps with your decision making.

Thanks for sharing your experience! That's exactly what I'm dealing with, good to know I'm not alone with this issue. The coils and spark plugs fix sounds like it might be the answer I'm looking for. Do you mind if I ask how much you ended up paying for the whole repair? Also, has everything been running smoothly since then, or have you noticed any other issues pop up?

Hey again! Just wanted to follow up, you'll be glad to hear I was right about the ignition coil being the culprit. After your message, I actually took my car to get it checked out, and sure enough, that's exactly what it was. The mechanic found a defective ignition coil and fixed the cable connection that was causing all the trouble. Only set me back 95€, which was a relief since I was worried it might be something way more expensive! Since getting it fixed, my BMW's been running like a dream, no more jerking, stalling, or rough idling. It's been about six months now, and I haven't had a single issue pop up. Honestly, it feels like driving a different car! The engine's smooth as butter, and that annoying check engine light is finally off. Pro tip from my experience, getting it fixed sooner rather than later was definitely the right call. These things can snowball into bigger problems if you let them go too long. Let me know if you need anything else! Always happy to help a fellow BMW owner.

Thanks so much for the detailed response! I actually just got back from the mechanic today and wanted to update everyone. You were spot on, it was definitely the ignition coils causing all the trouble. I bit the bullet and took it in yesterday after our chat. The mechanic found two faulty coils and some worn spark plugs. He showed me the old parts, and they were in rough shape! The whole repair, including parts and labor, came to around 300 bucks. I know it's not cheap, but considering how badly it was running, I'm just relieved it wasn't something more serious. Took it for a test drive right after, and what a difference! No more jerking or stalling, and that annoying check engine light is finally off. The engine's purring like it should now. Honestly wish I'd done this sooner instead of worrying about it for weeks. Thanks again for sharing your experience, it really helped me make the decision to get it fixed before it turned into something worse!