BMW M4 Rough Running Issues, Fix & Symptoms Guide

Hey there! I have some experience working on BMWs as a hobby mechanic. Had a similar issue with my 2015 BMW M3 last year (also own a 3-series). The symptoms you're describing sound exactly like what I dealt with. Mine turned out to be a leak in the exhaust system, which was causing those exact symptoms, rough running, jerking, and limp mode. The mechanic found cracks near the manifold. Got it fixed at my regular workshop for about 265 Euro, parts and labor included. The car's been running smooth since then. Before jumping to conclusions though, could you share: Current mileage on your M4? Any recent modifications? Are you getting any specific error codes? This info would help narrow down if we're dealing with the same issue. These symptoms can sometimes point to other problems too, so best to be sure.

Thanks for your detailed response! My M4 just hit 23857 KM and had its last major service about 3 months ago. No mods at all, keeping it stock for now. I'll definitely check for exhaust leaks, that price for the fix sounds much better than what I was dreading! Unfortunately, I haven't scanned for error codes yet, but planning to get that done tomorrow. Really appreciate you sharing your experience with a similar issue. It's giving me some hope that this might be a straightforward fix rather than something major!

Hey again! Glad to help out! After reading about your mileage and service history, I'm even more convinced it could be similar to what I experienced. Just to add to my previous response, when I first had these issues with my M3, I also initially panicked thinking it was something major. Mine had around 25000 KM when the problems started, pretty close to yours. The fact that yours is stock like mine was actually makes diagnosis easier, since there are no aftermarket parts complicating things. Quick tip: when you get those error codes tomorrow, feel free to post them here. That really helped me confirm it was the exhaust leak before taking it to the shop. Also, while you're getting it scanned, have them check the manifold area specifically, that's where my leak was, and it's a common weak point on these engines. Just keep in mind that even though our symptoms match up pretty well, it's still best to get a proper diagnosis. Let us know what the scan reveals, I'm really curious to see if it's the same issue I had with mine!

Thanks so much for all this helpful info! Just got back from getting those error codes checked, you won't believe it, but looks like we're dealing with the exact same issue! Got code P0420 and P0430, which the tech said points to exhaust system problems. They did a smoke test and found small cracks near the manifold, just like you mentioned. Really glad I posted here before freaking out too much. You saved me a ton of stress, I was imagining the worst! Got it booked in for repairs next week, and they quoted pretty much the same price range you mentioned. Can't tell you how relieving it is to know this is a fairly common and fixable issue. Honestly, huge thanks for taking the time to share your experience. It's exactly why I love these car communities, there's always someone who's been through it before and can help point you in the right direction. I'll probably post an update once it's all fixed up!