BMW X7 Boost Issues: Power Loss and Fuel Efficiency Drop

Hey there! I had a pretty similar issue with my 2018 BMW X5 last year. I've got some experience working on cars, but nothing too advanced. My symptoms matched yours exactly, poor acceleration, engine light, and terrible fuel economy. After taking it to my trusted workshop, they diagnosed a faulty vacuum switching valve. It was messing with the turbo boost control. I paid around 140 Euro for the fix, including parts and labor, and it's been running perfectly since then. Could definitely be the same issue on your X7, since they share similar engine components. Just curious, what engine variant do you have, and how many miles are on it? That info would help me share more specific details about the repair process I went through. Hope this helps point you in the right direction!

Thanks for sharing your experience! I've got the gasoline variant with 128036 KM on the clock. My last service was actually due recently, but I've been putting it off, probably not the smartest move given these symptoms. Really helpful to know about the vacuum switching valve, that makes a lot of sense given what I'm experiencing. The pricing sounds reasonable too, definitely better than what I was fearing. Might need to get it checked out sooner rather than later before it turns into something bigger.

Hey again! Glad I could help earlier. Yeah, putting off service isn't great, learned that the hard way myself. Just want to add that with my X5, I initially tried to wait it out thinking it wasn't a big deal, but that actually made things worse. The poor fuel economy alone was costing me more than the repair would have! Speaking of which, my car had around 115000 KM when this happened, so pretty close to where yours is now. The vacuum switching valve is a common wear item on these engines. After I got mine fixed, my mechanic mentioned that these issues often show up around the 100-120K mark. Quick tip: when you take it in, ask them to check the surrounding hoses too. In my case, they found a slightly cracked hose while doing the repair. Got that replaced at the same time, which probably saved me from another workshop visit a few months later. The symptoms you're describing are pretty much identical to what I experienced, so I'd bet good money it's the same issue. Better to get it sorted soon, you'll notice the difference immediately in how the car drives.

Thanks so much for the detailed follow-up! Really appreciate the tip about checking the hoses, that's exactly the kind of insider knowledge I was hoping for. You're absolutely right about the fuel economy issue; I've been spending way too much at the pump lately trying to ignore this problem. Just called my regular workshop and booked it in for tomorrow morning. Will definitely mention both the valve and hoses to them. What a relief to hear from someone who's been through the exact same thing. Was getting worried it might be something major with the turbo itself. This has definitely helped put my mind at ease about the whole situation. Will update the forum once I get it sorted in case anyone else runs into the same problem. Thanks again for all your help!