BMW Z4 Misfire Issues, Help with Rough Running Engine

Hey there! I've got some experience working with BMWs, I had a pretty similar issue with my '01 BMW 3 Series (also owned an X3). As someone with some experience working on cars, those symptoms sound very familiar. Had the exact same problems, rough running, jerky acceleration, and the dreaded check engine light. Turned out to be a faulty fuel injector. Got it fixed at my regular workshop last year, set me back about 515 Euro, but the car's been running like a dream since. Could definitely be the same issue with your Z4, but I'd need more info to be sure. Current mileage? When was the last time you had injector maintenance? Any other warning lights besides check engine? Does it happen more when the engine's cold or warm? The engines in these models are quite similar, so I might be able to give you more specific advice once I know these details.

Thanks for the response! My Z4 just hit 126257 KM and had its last service about two months ago. No other warning lights besides the check engine light. The jerking and rough running seems worse when the engine is cold, especially during the first 10-15 minutes of driving. I actually went ahead and had a diagnostic scan done yesterday, it's showing multiple cylinder misfires. Haven't done any specific injector maintenance that I can recall, so you might be onto something with the fuel injector suggestion. The symptoms you described with your BMW sound spot-on with what I'm experiencing. I'll definitely have my mechanic take a closer look at the injectors. Really appreciate you sharing your experience, helps narrow down where to start looking!

Hey again! Thanks for following up with those details. Yeah, those symptoms with your Z4 sound exactly like what I dealt with on my BMW. The cold-start issues and mileage really strengthen my suspicion about the injectors. After dealing with my injector problems last year, I actually learned that these symptoms are pretty classic signs of worn-out fuel injectors in these engines. Mine was also acting up more during cold starts, just like yours. The multiple cylinder misfires showing up on your scan is another red flag, that's exactly what my diagnostic showed too. Since you mentioned no specific injector maintenance, it's definitely worth checking out. These parts typically start showing their age around the 120K mark, which is right where your car's at. When my mechanic replaced my faulty injector, he recommended doing all of them at once to prevent similar issues from popping up with the others soon after. I'd say take it to your mechanic and specifically mention the injector concern. The diagnostic results plus the cold-start issues make it pretty likely that's your problem. Better to sort it now than wait for it to get worse, learned that the hard way with mine! Let me know what your mechanic finds. Always happy to share what I've learned from my BMW adventures!

Thanks so much for the detailed follow-up! This is exactly the kind of firsthand experience I was hoping to get. It's really helpful knowing that your BMW had the same symptoms, especially the cold-start issues. You've definitely convinced me about the injectors being the likely culprit. I've actually just called my mechanic and booked the car in for next week. Mentioned everything we discussed about the injectors, and he agreed it sounds like a probable cause. I'll take your advice about considering replacing all of them, makes sense to do it preventively rather than dealing with more issues down the line. Really appreciate you taking the time to share your experience and knowledge. Having someone who's been through the same thing makes me feel much more confident about getting this sorted. I'll update the thread once I get the diagnosis from my mechanic! Thanks again for all your help!