BMW Z4 Power Loss & Rough Running: Lean Condition?

Hey there! I have some experience working on cars and had a very similar issue with my 2016 BMW M2. Actually, when you described those symptoms, it immediately reminded me of what I went through. Had the exact same problems, rough running, jerking, and that annoying Check Engine Light. Took it to my trusted workshop and it turned out to be a faulty fuel injector. The repair set me back about 515 Euro, but it fixed all those issues you're describing. The car's been running smooth as silk since then. Before you proceed, could you tell us: Have you noticed any unusual fuel consumption lately? Does it misfire more when the engine is cold or warm? Any unusual exhaust smoke? Knowing these details would help confirm if you're dealing with the same injector issue I had. The symptoms definitely sound familiar, but it's always good to be sure before jumping to conclusions.

Thanks for sharing your experience with the M2! I've got 145284 KM on my Z4, and yeah, I've definitely noticed increased fuel consumption lately, about 15-20% more than usual since these issues started. The misfiring seems worse when the engine is cold, especially during the first 5-10 minutes of driving. No weird smoke from the exhaust though. Had my last service about 3 months ago and everything was fine then. This started pretty suddenly last week. Your injector situation sounds pretty similar to what I'm experiencing. Did you get any specific error codes when your issue happened? I'm thinking of scanning mine tomorrow, just trying to gather as much info as possible before heading to the shop.

Yeah hearing about your fuel consumption and cold misfires, I'm even more convinced it's the same injector issue I had with my M2. When I scanned mine, I got P0171 and P0174 codes, which basically pointed to the lean condition. The increased fuel consumption you're seeing makes total sense, my M2 was doing the exact same thing. The faulty injector wasn't spraying fuel properly, so the engine computer kept trying to compensate by adding more fuel overall. That's why you're burning through more gas than usual. The cold start issues you're describing? Spot on with what I experienced. Mine was particularly rough in the mornings, then would somewhat smooth out once warmed up, though it never ran quite right until I got it fixed. Just a heads up, when I first noticed these symptoms, I thought I could maybe drive it for a while longer, but my mechanic later told me I was lucky I brought it in when I did. Running lean can really mess up your engine if left unchecked. With those symptoms matching mine so closely, I'd definitely get it checked out soon. The repair cost was worth every penny for the peace of mind and smooth running afterward. Let us know what you find out after the scan!

Thanks so much for all the detailed info! You've really helped put my mind at ease about what might be going on. I'll definitely get it scanned tomorrow and won't risk driving it much until it's fixed. Really appreciate the heads up about potential engine damage, that's convinced me to get it sorted ASAP rather than trying to wait it out. Honestly, the repair cost you mentioned isn't as bad as I was fearing. Was worried it might be something way more serious and expensive. Will make an appointment with my mechanic right away and make sure to mention the injector possibility based on your experience. Really grateful for you taking the time to share your experience in such detail. I'll update the thread once I get it diagnosed and fixed, might help someone else dealing with similar issues down the line. Thanks again for all the help!