BMW 2 Series Limp Mode & Smoke: Help With Diagnosis

I had similar issues with my 2016 BMW 3 Series last summer. The symptoms matched yours exactly, limp mode, jerking during acceleration, and smoke from the exhaust. Turned out to be carbon deposits in the combustion chamber. Took it to a specialist who did a proper walnut blasting of the intake valves and cleaned the fuel injectors. They also had to replace two ignition coils that were damaged from the misfiring. It was quite a serious job as the deposits were affecting engine performance and could've led to more damage if left untreated. My advice, don't delay getting it fixed. These symptoms typically won't resolve themselves and could cause more engine damage. Make sure whoever works on it has experience with direct injection engines, as they're prone to carbon buildup. The whole service took about a day and a half at my garage. From your description, sounds like you're dealing with the same issue. Those symptoms are classic signs of carbon deposits, especially at that mileage.

Thanks for sharing your experience! Sounds exactly like what I'm dealing with. The carbon deposit buildup makes total sense given the symptoms. Quick question, do you remember roughly how much they charged you for the whole service? Also, has everything been running smoothly since the repair, or have you noticed any other issues pop up? I just want to get an idea of what I'm looking at cost-wise and whether it's a long-term fix or if I should expect other related problems down the line.

Hey there! Happy to give you an update. The total bill came to 425 € for cleaning out those carbon deposits in the combustion chamber, and I've got great news, the knocking problem is completely gone now! The car's running like a dream since the service, which was about 8 months ago. No more jerking, no more smoke, and the engine's got its power back. I've been keeping a close eye on it since then and honestly haven't noticed any other issues pop up. It really seems like it was a solid fix. The mechanic did recommend regular fuel system cleaning every 50k km or so to prevent the deposits from building up again, which makes sense. I'm actually using better quality fuel now too, just as a preventive measure. The price was totally worth it considering how much better the car runs now. Trust me, you'll notice the difference immediately after getting it fixed. My BMW feels like new again, smooth acceleration, no more limp mode, just pure driving pleasure like it should be.

Just wanted to update you all on my BMW situation. Took your advice and got it sorted last week. You were spot on about the carbon deposits! Found a specialist mechanic who really knew his stuff. The whole service cost me about 480 €, a bit more than yours because they had to replace an oxygen sensor too. what a difference! The car's running like new again. No more smoke, jerking's gone, and that annoying limp mode is history. Actually had a proper drive yesterday and couldn't stop grinning, forgot how smooth this thing could be! The mechanic walked me through everything they did, showed me the gunked-up parts they cleaned, and even gave me some tips about preventing future buildup. Thanks again for sharing your experience, really helped me make the decision to get it fixed straight away instead of putting it off. Definitely learned my lesson about regular maintenance. Already marked my calendar for the next fuel system cleaning, and I've switched to premium fuel. Better to spend a bit more now than deal with bigger problems later!