BMW 5 Series Rough Running & Limp Mode, Help Needed

Hey there! I had pretty similar symptoms with my 2003 BMW 3 series (know a bit about cars, worked on them as a hobby). The rough running and jerking were exactly what I experienced. After some back and forth with my mechanic, we found a nasty leak in the exhaust system that was messing with the oxygen sensors and causing those exact issues, check engine light, limp mode, the works. Got it fixed at my local workshop, total bill came to 265 Euro. Once they replaced the leaking section, the car ran smooth as butter again. Those symptoms disappeared completely. Could definitely be something similar with your 5 series, but mind sharing a few more details? Like the mileage, any unusual sounds, and if you notice any specific points when the jerking gets worse (like when cold or at certain speeds)? That'd help nail down if it's the same issue I had.

Thanks for sharing your experience! My 5 series's got 117217 KM on the clock, and I just had it serviced last month. The jerking seems most noticeable when I'm accelerating, especially between 2000-3000 RPM. I've noticed it's actually worse when the engine's warm, which is kind of weird. No unusual sounds that I can pick up, just that unstable running feeling. Interesting that you mention the exhaust leak, I'll definitely get that checked out. Did you notice any specific exhaust smell before you got yours fixed?

Hey again! Yeah, now that you mention those specifics about when the jerking happens, I'm starting to think my initial guess about the exhaust leak might not be the whole story. With my 3 series, the symptoms were actually pretty consistent regardless of engine temp, unlike what you're describing. Come to think of it, when my exhaust was leaking, I definitely noticed a stronger exhaust smell, especially when idling. If you're not getting that, we might be looking at something different here. Since you mention it's worse between 2000-3000 RPM and specifically when warm, it's starting to sound more like it could be ignition coil related. I actually had that issue crop up about a year after the exhaust problem, same jerking sensation in that exact RPM range, and it was definitely worse when warm. Ended up replacing two coils and a set of spark plugs, and that sorted it right out. Cost was a bit less than the exhaust repair, around 180 Euro for parts and labor. Have you noticed if the check engine light flashes when the jerking happens? That was another tell-tale sign in my case. If it does, I'd put money on ignition coils being the culprit.

Thanks for that detailed response! After reading what you shared about the ignition coils, I'm thinking that's probably what's going on with mine too. You basically described my exact situation, and yes, now that you mention it, I have noticed the check engine light flashing during those rough moments! I'll definitely get the coils and plugs checked out first. Never thought about the correlation between the warm engine and the symptoms, but it makes total sense now. The price you mentioned sounds way better than what I was worried I might have to spend, especially since I was dreading some major engine work. Really appreciate you taking the time to share your experience, it's given me a much clearer direction on what to have the mechanic look at. Will book it in this week and hopefully get this sorted out quickly!