BMW i3 Power Loss: Bad Manifold Sensor Alert

Had a similar issue with my 2020 BMW i8 Hybrid last month. My symptoms matched yours exactly, power loss, increased fuel consumption, and the dreaded check engine light. Took it to the garage and they diagnosed a major vacuum leak in the intake system. The manifold pressure sensor was reporting incorrect readings because of the leak, but wasn't the root cause. Turned out the gasket between the intake manifold and cylinder head had deteriorated pretty badly. It was a serious job that required taking apart quite a bit of the engine bay to access and fix properly. The mechanics had to remove the intake manifold completely to replace the gasket and check for any other potential leaks. They also cleaned the throttle body while they were in there since it was showing signs of carbon buildup. The car's running like new now, power is back, fuel economy is normal, and no more check engine light. Based on your symptoms, I'd recommend getting it checked soon before it potentially causes more issues.

Thanks for sharing your experience, that's super helpful! The vacuum leak diagnosis makes total sense given what happened with my i3. I'm relieved to hear you got it sorted out properly. Do you remember roughly how much the whole repair ended up costing you? Also, has everything been running smoothly since the fix, or have you noticed any other quirks popping up? Would love to know since I'm trying to budget for this repair and want to make sure I'm prepared for any potential follow-up issues.

Hey again! Yeah, happy to fill you in on the details. Just got back from the mechanic actually, they found and fixed the faulty manifold pressure sensor, but the main culprit was indeed that vacuum leak I mentioned before. Total bill came to 235 € for the whole job, which honestly wasn't as bad as I was expecting given how much work they had to do. Since the repair, my i8's been running absolutely fantastic, like a completely different car! No more power issues, fuel economy is back to normal, and that annoying check engine light hasn't shown its face again. It's been about six weeks now and zero quirks or problems to report. The repair shop did a really thorough job, cleaned everything up while they were in there, and even gave the throttle body a good cleaning as I mentioned before. Sometimes these issues can cascade into bigger problems if left unchecked, so I'm glad I got it sorted when I did. Trust me, you'll notice the difference immediately once you get yours fixed!

Thanks for all the details! I actually just got back from the mechanic myself and wanted to share how it went. Found a reputable shop and they did a fantastic job. You were spot on about the vacuum leak being the main issue. Funny enough, they also found some carbon buildup that needed cleaning. The whole repair took about four hours, but it was worth the wait. The total cost came to a bit more than yours because they had to replace a couple of worn-out hoses too, but I'm just glad it's fixed. The car feels completely different now, way more responsive and the fuel economy has improved dramatically. Thanks again for helping me figure this out. Really appreciate you taking the time to share your experience. It made me feel much more confident about getting it repaired instead of putting it off. Now I know exactly what to look out for in the future too!