BMW X7 Power Loss & Poor MPG: MAP Sensor Issues?

Hi there! I have some experience working on cars and had a similar issue with my 2020 BMW X5 last year (my family also owns an X3). The symptoms you're describing sound exactly like what I dealt with, check engine light, sluggish response, and burning through fuel like crazy. Turned out I had a major vacuum leak. The workshop found cracks in the intake manifold gasket that were causing all sorts of problems. The repair cost me around 235 Euro, including parts and labor. After fixing it, the car ran like new again. Before I share more specific details about my repair experience, could you share: Have you scanned for error codes? Any unusual sounds when accelerating? When did these symptoms first appear? This would help me better understand if you're facing the same issue I had.

Hey, thanks for sharing your experience! My X7 just hit 191211 KM and had its last service about a month ago. I did get the error codes scanned at a local shop, it's showing P0299 which points to the turbo/supercharger underboost condition. No weird sounds really, just that annoying power loss. The symptoms started showing up gradually over the past week. I'm really hoping it's just the gasket like in your case and not something more serious with the turbo itself. The fuel economy is killing me right now. Let me know if those symptoms match up with what you experienced, I'd rather avoid a costly turbo replacement if possible!

Hey again! Thanks for providing those details. Oh when you mentioned P0299, it definitely brought back memories. My X5 actually threw the same code before I got it sorted. Looking at your symptoms and mileage, I'm even more convinced it's similar to what I faced. While my initial thought was just the manifold pressure sensor, it turned out the vacuum leak from that bad gasket was causing the underboost condition. The turbo itself was perfectly fine! Here's what cemented it for me, the gradual onset of symptoms is exactly how mine played out. Started with slightly worse fuel economy, then progressively got worse over about 8-9 days until the power loss became really noticeable. Quick tip from my experience, have them check the boost pressure lines too while they're at it. My mechanic found a small crack in one of those as well. Getting both fixed in one go saved me from having to go back again. Trust me, don't panic about the turbo just yet. Get those gaskets and lines checked first. In my case, the repair was way more straightforward (and cheaper!) than I initially feared. Keep me posted on what you find out!

Thanks so much for the detailed response! You've honestly made me feel a lot better about this whole situation. I was really stressing about potentially having to replace the entire turbo, but hearing that you had the exact same code and symptoms, and it turned out to be just a gasket issue, is such a relief. I'll definitely get those boost pressure lines checked too, that's a great tip! I've already called my mechanic and booked it in for tomorrow morning. They actually mentioned they'd start with checking the gaskets and lines before jumping to any conclusions about the turbo, which aligns perfectly with what you're saying. Really appreciate you taking the time to share your experience in such detail. I'll update the thread once I get it sorted, just in case someone else runs into the same issue with their X7. Thanks again for helping me avoid unnecessary panic and expenses!