BMW i8 Stalling: Air Valve or Something Sinister?

I had nearly identical issues with my 2015 BMW i3. The symptoms you're describing sound very familiar, I dealt with the same erratic behavior from the secondary air pump and engine performance issues. In my case, it turned out to be a deteriorated hose connection between the pump and valve. I initially thought it was just the valve, but during inspection at the garage, they found the rubber hose had micro-cracks causing air leaks. These leaks were making the pump work overtime and causing those stalling issues. The fix required replacing both the hose assembly and the connecting valve. It wasn't a quick job since they had to access some tight spots, but it wasn't a major mechanical crisis either. The stalling completely stopped after the repair, and the check engine light hasn't returned. Just make sure whoever works on it is certified for hybrid BMW systems, these cars have specific requirements for servicing.

Thanks for sharing your experience, it's really helpful to hear about a similar case! That makes a lot of sense about the hose connection being the culprit. If you don't mind me asking, how much did you end up paying for the whole repair? Also, has everything been running smoothly since then, or have you noticed any other quirks pop up? I want to make sure I'm prepared for what I might be facing with my i8.

Hey again! Glad to help follow up. Yes, I got it all sorted out, took it to the mechanic last week and you'll be happy to know it was exactly what I suspected. The hose connection from the pump to the valve was definitely the problem. They fixed it up for 175 Euro, which honestly wasn't as bad as I was expecting for a BMW repair! Since the fix, everything's been running like a dream. No more stalling, no more jerking, and that annoying check engine light is finally gone. The secondary air pump is working exactly as it should now, no more weird running times or cutting out. It's such a relief to have it sorted. Haven't noticed any other issues popping up either. The car's back to its smooth, quiet self. Just goes to show that sometimes the simpler explanation is the right one, it wasn't some complex electronic issue, just a basic hose connection that needed fixing. Hope this helps you get yours sorted too!

Thanks everyone for the help! I took my i8 to a certified mechanic yesterday, and wow, what a different experience from my last repair shop! Turns out it was exactly what you described, a faulty hose connection causing all those issues. They showed me the old hose with the tiny cracks, and honestly, I'm just glad it wasn't something more serious. The repair cost was a bit higher than yours since they had to order a specific part for the i8, but still way better than I was expecting. The best part? The car's running perfectly now, no more stalling, no more jerking, and that annoying check engine light is finally off. The secondary air pump is working just like it should. Really appreciate everyone's input, helped me avoid getting ripped off and gave me the confidence to get it checked out properly. Nothing better than having your car back in top shape! Marking this one as solved.