BMW 5 Hybrid: Hissing & Stalling Nightmare Needs Fix

Hey there! I had nearly identical issues with my 2017 BMW 7 Series Hybrid last year. The symptoms matched yours exactly, rough acceleration, stalling, hissing noise, and failed emissions. Turned out my intake hose had a significant tear near the throttle body, causing a major vacuum leak. The diagnostic was pretty straightforward at the garage. They used smoke testing to identify the leak location. What started as a simple hissing noise could have led to some serious engine damage if left unchecked, as the engine was pulling in unmetered air and running lean. The fix involved replacing the intake hose and cleaning the throttle body. The check engine light cleared up right after, and the car's been running smoothly since. It was a relatively simple fix but definitely not something to ignore. Based on my experience, I'd recommend getting it checked soon. Those symptoms aren't going to improve on their own, and you might risk more extensive damage to your engine if you keep driving it in this condition. Best of luck getting it sorted.

Thanks so much for sharing your experience! That's really helpful to know it was the intake hose in your case. The symptoms do sound exactly like what I'm dealing with. I'm glad you got it sorted out with just a hose replacement and throttle body cleaning. Do you remember roughly how much the repair set you back? Also, have you had any similar issues pop up since the fix? Just want to make sure I'm prepared for what's coming.

Hey again! Great to hear back from you! Since my last post, I actually got my car fixed at the mechanic's this week, and guess what? It was exactly what I suspected: an air intake system leak. Just like my previous BMW, the intake hose was the culprit. The repair was pretty straightforward and only cost me 100 € to fix the leaking hose. To answer your questions, no, I haven't had any similar issues pop up since my previous repair on my 2017 7 Series, and I don't expect any with this recent fix either. These intake hoses are generally pretty reliable once replaced, as long as they're installed properly. My car's running like a dream now, no more hissing sounds, the acceleration is smooth again, and I'm sure it would pass an emissions test with flying colors. It's amazing what fixing one small component can do! Just make sure you get it checked out soon. Like I mentioned before, putting it off could lead to bigger problems. For what it's worth, the peace of mind after getting it fixed is totally worth it. Let me know how it goes when you get yours looked at!

Thanks for the update about your recent repair! That's really encouraging to hear it was such a simple and affordable fix. I actually took your advice and booked an appointment with a mechanic for tomorrow morning. Had a terrible experience last time at a different shop where they quoted me way more for what seemed like unnecessary repairs. But hearing your success story with both BMWs makes me feel much better about getting this sorted. I've been babying the car, driving less and avoiding highway speeds until it's fixed. I'll definitely post an update once I get the diagnosis. Fingers crossed it's just the intake hose like yours! Really appreciate you sharing your experience, it's helped me feel more confident about handling this issue.