BMW 5 Series Diesel Stumbles: Bad Manifold Flap Control?

Hi there! I experienced the exact same symptoms with my 2010 BMW 3 Series diesel a while back. The hissing noise and jerky acceleration were identical to what you're describing. In my case, it was indeed the intake manifold control switch that went bad. Had it fixed at the garage, they replaced the intake manifold actuator and cleaned the manifold flaps, as they were stuck due to carbon buildup. The whole job took about 4 hours. It's a fairly serious issue since it affects engine performance and emissions, but it's completely fixable. After the repair, the engine ran smooth again, power was back to normal, and fuel consumption dropped back to regular levels. I'd definitely recommend getting it checked soon to prevent any additional damage to other components.

Thanks for sharing your experience Mark. Really glad to know I'm not alone with this problem. Your description matches my situation perfectly, especially that hissing noise! Just wondering, do you remember roughly how much you paid for the repair? Also, has everything been running smoothly since the fix, or have you noticed any other issues pop up? I'm trying to get a better idea of what I'm getting into before heading to a garage.

Hey again! Absolutely happy to share the details! Just got back from having mine fixed last month, paid exactly 465 € for the intake manifold control switch replacement. Honestly, what a relief it's been since then! The car's running like a charm now, no more of that annoying hissing noise or jerky acceleration that was driving me nuts. The best part? My fuel consumption is back to normal, and the engine's performing beautifully. Haven't had a single problem since the repair. Trust me, it's worth every penny to get it sorted properly. The mechanic did a thorough job cleaning those manifold flaps too, which probably helped prevent any future issues. I know you're worried about choosing a garage after your last experience, but getting this fixed sooner rather than later is definitely the way to go. Your symptoms are textbook for this problem, and it's pretty straightforward for a decent mechanic to fix. Let me know how you get on! Mark

Thanks so much for all the detailed info! I actually just got back from the mechanic today, and you were spot on with everything. Found a really good shop through a 's recommendation, and they diagnosed it right away. The intake manifold was exactly the culprit. Funny enough, my repair cost was pretty similar to yours. The mechanic was super transparent about the whole process and even showed me the gunked-up parts they removed. What a difference now, my car's running smoother than it has in months! No more scary hissing sounds or jerky movements when I accelerate. Best decision I've made in a while getting this fixed. The fuel consumption has already improved dramatically on my drive home. Really appreciate you taking the time to share your experience, it gave me the confidence to get this sorted before it turned into something worse. Thanks again for the help!