BMW 7 Diesel Power Loss & Jerking: Fix Needed

Hey! I have some experience working on cars and had a very similar issue with my 2003 BMW 5 series diesel (similar engine family to your 7). The symptoms you're describing are exactly what I experienced, poor performance, jerking, and that distinctive hissing noise. Had it checked at my workshop and it turned out to be a faulty intake manifold control switch. Got it replaced and it cost me around 465 Euro, but the car has been running like a charm since then. The whole repair took about half a day. Before jumping to conclusions though, could you share: Current mileage? Any warning lights on the dash? Does it happen more when the engine is cold or warm? My mechanic mentioned these issues are fairly common on these BMW diesels from that era, especially the 5 and 7 series. Let me know these details and I might be able to help you further!

Thanks for the detailed response! My current mileage is 138033 KM, and I just had my service last month. The problems occur mostly when the engine is warm, and no warning lights on the dash yet. What's interesting is that the symptoms match exactly what you described with your 5 series. Did your mechanic mention anything about potential damage if this isn't fixed quickly? I'm a bit worried about driving it in this condition.

Hey again! Thanks for the follow-up. Yeah, I totally get your concern about potential damage, I was in the same boat with my 5 series. From my experience, you definitely don't want to keep driving it too long in this condition. My mechanic was pretty clear that prolonged issues with the intake manifold flap can lead to bigger problems. In my case, I kept driving it for about two weeks before getting it fixed, and I noticed the symptoms were getting progressively worse. The increased fuel consumption alone was hitting my wallet pretty hard, but more importantly, there's a risk of carbon build-up in the intake system if it's not working properly. My mechanic showed me the old parts when they replaced them, and there was already some nasty build-up starting to form. With your mileage being similar to what mine was when it happened (I was at about 142000 km), and the symptoms showing up when the engine is warm, it's almost certainly the same issue. I'd recommend getting it checked out sooner rather than later, it's not worth risking more expensive repairs down the line. One thing I learned from this: these intake manifold issues on our BMWs from that era are pretty much a wear and tear item. Since getting mine fixed, I've had zero issues with power loss or that annoying hissing sound. The car runs like new again.

Thanks so much for all this info, it's really helpful to hear from someone who's been through the exact same thing. You've convinced me not to put this off any longer, especially hearing about that carbon build-up risk. I'll call my mechanic first thing tomorrow to get it checked out. Better to spend the money now than risk bigger problems later. Really appreciate you taking the time to share your experience, it's definitely made me feel more confident about what needs to be done. I'll probably end up following the same repair route you did since our situations seem so similar. Thanks again for all the advice!