BMW 8 Series: Engine Issues & Poor Throttle Response

Hey there! I have some experience working on BMWs, and this sounds familiar. I had a similar issue with my 2019 BMW 7 Series last year. When you mentioned those symptoms, it instantly reminded me of my situation. My car was showing the exact same signs, poor acceleration, high fuel consumption, and that annoying check engine light. Took it to my regular workshop, and they found a large vacuum leak. The rubber hoses had deteriorated and were causing all sorts of problems. Total fix was around 235 Euro, and the car's been running like a charm since. Before I share more specifics, could you tell me your engine size and mileage? That would help me confirm if it's the same issue I dealt with. Also, are you getting any specific error codes?

Thanks for sharing that! My car's at 198036 KM and had its last service about 2 months ago. What you're describing sounds spot on, especially the vacuum leak part. I'm running the 3.0L gasoline engine and honestly was hoping it wouldn't be anything major. I haven't pulled the error codes yet, was planning to do that tomorrow. Did you notice any hissing sounds before getting yours fixed? I'm trying to compare symptoms before heading to the workshop.

Hey again! Wow, what a coincidence, my 7 Series also has the 3.0L engine! Yeah, I definitely remember hearing a subtle hissing sound, especially when idling. It was most noticeable early in the morning when everything else was quiet. In my case, the error code was P0171 (System Too Lean), which makes sense given the vacuum leak. The mileage on mine was pretty close to yours too, around 185000 KM when it happened. These rubber hoses tend to get brittle and crack right around that mileage mark. Quick tip from my experience, when they fix it, make sure they check all the vacuum lines, not just the obviously damaged ones. My mechanic found a second smaller crack while doing the repair, and I'm glad he caught it before it became another problem. Would have been super annoying to go back a month later for the same issue. Since you mentioned your car was serviced recently, did they say anything about the condition of the hoses during the inspection? Sometimes these issues can develop pretty quickly, but there might have been early warning signs. Let me know what codes you get tomorrow, I'm curious if they match what I had. These BMWs are great cars, but they do have their quirks!

Thanks for the detailed response! Just got back from checking those error codes, and wouldn't you know it, P0171 showed up, exactly like yours did! Had my wife listen for the hissing sound this morning and she spotted it right away near the front of the engine. You know what's really frustrating? Looking back at my service records from two months ago, they noted "minor wear on vacuum lines" but said it wasn't urgent yet. Guess they were a bit off on that timeline! Should've pushed them to replace those hoses right then and there. Really appreciate all your help and the heads-up about checking all the lines. Going to book it in tomorrow and specifically mention checking all vacuum lines, not just the obvious ones. Quick question though, after your repair, how long did it take for the engine to return to normal performance? Just trying to set my expectations right. Thanks again for taking the time to help out. It's such a relief knowing someone else dealt with the same issue and got it sorted without breaking the bank!