BMW X4 Engine Light and Power Loss: Manifold Issues?

Hey there! I have some experience working on BMWs. Had a similar issue with my 2019 BMW X3 last year. The symptoms you're describing sound exactly like what I went through, sluggish acceleration and terrible fuel economy. Took it to my trusted workshop where they found a large vacuum leak. After diagnosis, they discovered a cracked hose near the intake manifold. Total repair cost me around 235 Euro, but the car runs like new now. Worth every penny! Before suggesting anything specific, could you share: Any unusual sounds when accelerating? Did the issue start suddenly or gradually? Have you noticed any strange idle behavior? By the way, if you own an X4 M40i, the setup is quite similar to my old X3, so I might be able to provide more specific insights.

Hey, thanks for your detailed response! I've got only 11032 KM on the clock since my last service. Actually yes, I've noticed a slight whistling sound during acceleration, and the idle has been a bit rough lately. The issue started gradually over the past week or so. Initially thought it was just bad fuel, but it's getting worse. Your vacuum leak experience is quite interesting, might be worth checking that out. Would be a relief if it's just a cracked hose in my case too. The symptoms do sound very similar. Will get it checked at the workshop tomorrow. Really appreciate your help and insights on this!

Hey again! Thanks for the follow-up. That whistling sound you mentioned definitely rings a bell, it's exactly what I heard before discovering my vacuum leak. With only 11k km since your last service, I'd be really surprised if it was the manifold pressure sensor. In my experience, when the sensor fails, you typically don't get that whistling noise. The vacuum leak makes more sense given all your symptoms, especially that rough idle. When I had my X3 fixed, the mechanic showed me the cracked hose, it was barely visible to the naked eye, but enough to cause all those issues. Quick tip: if you're heading to the workshop tomorrow, try to pay attention to whether the whistling gets louder when you rev the engine. This helped my mechanic pinpoint the location of my leak faster. The good news is that if it is a vacuum leak like mine was, it's usually a pretty straightforward fix. Keep us posted on what they find, really curious to know if you've got the same issue I had. Always happy to share more details about my experience if you need them!

Thanks so much for all this helpful information! It's really reassuring to hear your experience, and I'll definitely keep an ear out for changes in that whistling sound before heading to the workshop. You're right, the symptoms are incredibly similar to what you experienced. Come to think of it, the whistling does seem to get more noticeable with higher revs, just like you mentioned. I'm feeling much more confident about the workshop visit tomorrow, at least now I can point them in the right direction with the vacuum leak possibility. And if it turns out to be just a cracked hose like in your case, that would be a massive relief both for my wallet and peace of mind! I'll definitely update this thread once I get it sorted. Really appreciate you taking the time to share your experience and tips. It's exactly the kind of firsthand insight I was hoping for when I posted this question!