BMW Z4 Rough Idle and Power Loss: MAP Sensor Failure?

I had nearly identical issues with my 2016 BMW M235i last month. The symptoms you're describing match my experience, power loss, rough idle, and increased fuel consumption. Initially, I also thought it was the pressure sensor, but when my mechanic checked, he found significant vacuum leaks around the intake manifold gasket and cracked vacuum lines. These leaks were causing false readings in the system. The repair involved replacing the gasket, several vacuum lines, and cleaning the throttle body. This was actually a serious issue that needed immediate attention as it was affecting engine performance and could have led to more expensive problems if left unfixed. The repair wasn't just a quick sensor replacement, it took about 4-5 hours of labor. My suggestion would be to get a proper diagnostic test first. Don't just assume it's the pressure sensor, as vacuum leaks can mimic those symptoms. Make sure they check the entire intake system thoroughly.

Thanks for sharing your experience, that's really helpful! I had a similar situation but ended up being luckier as it was just the sensor in my case. I'm curious though, do you remember roughly how much you paid for all that work? And has everything been running smoothly since the repair, or have you noticed any other issues pop up? Always good to know what to watch out for with these cars.

Hey there! Just wanted to follow up, actually got everything sorted with my M235i now. After the whole vacuum leak situation I mentioned before, I took it to a trusted mechanic who found and fixed a faulty manifold pressure sensor too. The vacuum leak repair set me back 235€, which wasn't too bad considering the amount of work involved. Everything's been running like a dream since then, no more power drops, fuel consumption is back to normal, and the engine's purring like it should. It's funny how these BMWs can be so sensitive to small issues, but once you get them fixed properly, they're absolutely brilliant to drive. Haven't had a single problem since the repair, which was about six months ago now. The car feels more responsive than ever, and I'm actually getting better fuel economy than before the issues started. Just goes to show how important it is to get these things checked out properly rather than trying quick fixes. If you're still having any niggles with yours, definitely get it looked at sooner rather than later, these engines really don't like being run when something's not quite right.

Really appreciate you following up about your repair! I finally got mine sorted out last week. The mechanic I found was spot-on, turned out it was indeed just the manifold pressure sensor playing up. Got it replaced for about 150€ including labor, which was much less than I'd feared. The whole experience wasn't nearly as painful as my last mechanic disaster. The car's running beautifully now, no more rough idle, power's back to normal, and fuel consumption has dropped back to what it should be. The engine light's finally off too, which is a relief. I actually learned a lot from this whole thing. Went in expecting the worst after hearing about your vacuum leak situation, but sometimes it really is just a simple fix. Just glad I didn't put it off any longer, could've ended up with bigger problems like you mentioned. Guess I'll stop worrying about every little noise now and just enjoy driving it again. Thanks for all your help, it really made me feel better about getting it sorted!