i8 Performance Issues: Check Engine + Power Loss Symptoms

Hi there! I have some experience working on hybrids, and your symptoms sound familiar. I actually had a similar issue with my 2017 BMW i3. The symptoms were almost identical, power loss, surging, and increased fuel consumption. After taking it to my trusted workshop, they diagnosed a faulty vacuum switching valve. This little component plays a big role in boost pressure control. The repair took about 2 hours, and I paid around 140 Euro for the fix. Since then, my car has been running smoothly. Before I can give you more specific advice, could you share: How many miles/kilometers are on your i8? Does the issue happen more in EV mode or when running on gas? Have you scanned for specific error codes? The i8 is a bit more complex than my i3, but the underlying hybrid systems share some similarities. Let me know these details and I might be able to help further.

Thanks for your response! I'm having this exact same issue with my i8 right now. I just checked, mine's at 85021 KM from the latest service, and I'm noticing these problems mainly when running in hybrid mode. Haven't had a chance to scan for codes yet, but I'm definitely going to check that vacuum switching valve you mentioned. Did you notice any specific conditions when your issues would get worse or better? The surging is really starting to bug me during my commute.

Hey again! Yeah, I definitely remember dealing with that frustrating surging in my i3. Since you asked, the issue was definitely more noticeable during warm-up and when accelerating from low speeds. It was particularly annoying when trying to merge into faster traffic, the car would hesitate and then suddenly surge forward. Not fun at all! In my case, I actually noticed the problems would get worse on humid days or after the car had been sitting for a while. The symptoms would sometimes temporarily improve after driving for about 15-20 minutes, but they'd always come back. Given your mileage and the symptoms you're describing, I'm even more convinced it's that vacuum switching valve. The fact that it's happening mainly in hybrid mode makes sense, that's when the system is working hardest to manage power between both motors. Quick tip though, before you head to the workshop, try cleaning the MAF sensor if you haven't already. Sometimes that can cause similar symptoms and it's an easy fix. But honestly, based on what you're describing, I'd put money on that vacuum valve being the culprit. Keep me posted on what you find out! Always interested to hear how these hybrid issues get resolved.

Thanks everyone for the insights! I just wanted to give a quick update, I called my workshop and described the symptoms, mentioning both the vacuum switching valve and MAF sensor that were suggested. They agreed these are likely culprits and I've booked the car in for next week. The surging definitely gets worse during those humid morning commutes, just like you mentioned. It's particularly bad when I'm trying to merge onto faster roads, really makes me nervous when I need that reliable acceleration. I'll make sure to get those error codes scanned before I take it in, just to give them more to work with. What's interesting is that after our chat, I paid more attention and noticed the issues do seem to improve a bit after about 20 minutes of driving, though they never completely go away. At least I'm not alone in experiencing this! I'll post back once I get the diagnosis and repair done. Really hoping it's just that vacuum valve, seems like a straightforward fix if that's the case. Thanks again for sharing your experience, it's been super helpful in narrowing down the problem!