BMW M2 Owner Seeks Help for Multiple Engine Issues

Hey there! I had nearly identical issues with my 2019 BMW M4 last year. The symptoms matched yours exactly, rough idle, jerking, hissing, and terrible fuel economy. Turned out to be a cracked intake boot between the mass airflow sensor and throttle body. The vacuum leak was causing unmetered air to enter the system, throwing off the air-fuel ratio completely. It's actually a fairly common issue as these rubber boots age and get brittle from engine heat. My mechanic showed me the split in the hose, it was pretty obvious once they knew where to look. This isn't a minor issue as it affects engine performance and emissions, but the fix itself isn't complicated. Had mine replaced along with the clamps, and all symptoms disappeared immediately. The engine went back to running smooth as silk. If you're experiencing these exact symptoms, I'd bet good money it's the same problem. Get it checked soon though, running with a vacuum leak isn't great for your engine long-term. Hope this helps!

Thanks for sharing your experience! It sounds exactly like what I'm going through with my M2. The sudden improvement after fixing the intake boot is really encouraging to hear. Would you mind sharing roughly how much the repair cost you? Also, has everything been running smoothly since the fix, or have you noticed any other issues pop up? Trying to get an idea of what I might be looking at cost-wise and whether I should be checking for related problems while it's being worked on. Thanks!

Hey again! Happy to give you an update! So after taking it to my mechanic last week, they confirmed it was indeed the intake hose leaking, just like I suspected when I first replied to you. The total repair came to 100 € and honestly, it was money well spent. Since getting it fixed, my M4's been running absolutely perfect. No more hissing, jerking, or any of those annoying symptoms we discussed. The fuel economy is back to normal too, which is a nice bonus for my wallet! Haven't had a single issue pop up since the repair. While they had it open, the mechanic did a quick check of the surrounding components, everything else looked solid, so you might not need to worry about related problems. But it's always good to have them take a look while they're in there. For what it's worth, I'd say just get it sorted sooner rather than later. The repair cost is pretty reasonable considering how much it improves the car's performance, and it prevents any potential long-term damage to your engine. Let me know how it goes when you get yours fixed!

Thanks a lot for all the detailed info! I actually just got back from the mechanic today. You were spot on, it was the intake boot causing all the trouble. The mechanic found a pretty nasty crack in it, just like you described. The repair was quick and didn't break the bank. They did a thorough check of the surrounding parts while they were at it, and everything else looked good. The difference in how the car runs now is like night and day! No more jerking or hissing, and it feels way more responsive. Took it for a good test drive, and I'm honestly amazed at how much better it feels. Engine's running smooth, and the check engine light's finally off. The mechanic was actually pretty honest and straightforward, which was refreshing after my last experience. Really appreciate you sharing your experience, it gave me the confidence to get it checked out instead of putting it off. Feels great to have my M2 back to its old self!