BMW i8 Owners: Engine Troubles & Stalling Issues Fixed?

I've got some experience working on hybrids, and had a really similar issue with my 2017 BMW i3. My friend actually has an i4, so I'm quite familiar with BMW hybrids. What you're describing sounds exactly like what I dealt with, rough running, stalling, the whole package. Turned out my high pressure pump was failing. Had to take it to my trusted workshop where they diagnosed and replaced it. The whole thing set me back about 1510 Euro, but it fixed all those symptoms you mentioned. Before I share more specific details about my repair experience, could you share: What's your current mileage? Any other warning lights besides the check engine? Have you noticed any unusual fuel consumption lately? This will help me understand if you're facing the same issue I had.

Thanks for sharing your experience! My i8 is at 94612 KM and just had its service last month. Yeah, no other warning lights right now except for the check engine light. Interesting that you mention the high pressure pump, that's definitely worth checking out. I haven't really tracked the fuel consumption lately, but now that you mention it, I think it might be using a bit more fuel than usual. Were there any specific noises or symptoms that confirmed it was the pump in your case? Just trying to compare notes before I head to the shop.

Hey again! Yeah, thinking back to my i3 situation, there were definitely some telling signs that pointed to the high pressure pump. The biggest giveaway was this sort of whining noise coming from the engine bay, especially when accelerating. It wasn't super loud, but once you noticed it, you couldn't un-hear it. At around 90K kilometers on mine, it started acting up just like yours, that inconsistent idle and the power loss were the first signs. The increased fuel consumption you're noticing is really similar to what I experienced too. I remember filling up way more often than usual before I got it fixed. The thing with these hybrid systems is they're pretty sensitive to fuel pressure issues. When I finally got it diagnosed, the pressure readings were way below spec. My mechanic showed me the old pump when they replaced it, the internal components were pretty worn out. Quick tip though, if you're heading to the shop, ask them to check the fuel pressure readings first. Could save you some diagnostic time and money. In my case, the numbers didn't lie, and once the new pump was in, it was like driving a different car. The idle smoothed right out, power came back, and that annoying whining noise disappeared completely. Let me know what you find out, really curious if it turns out to be the same issue!

Thanks so much for all that detailed info! Now that you mention the whining noise, I've actually been hearing something similar during acceleration, but I wasn't sure if I was just being paranoid. I'll definitely get those pressure readings checked first, that's a really smart approach. Going to book it in at the shop tomorrow and will specifically ask them to look at the high pressure pump. Your experience is incredibly helpful, especially since our mileage is pretty close. Really appreciate you taking the time to share all this, I feel much better equipped going into the repair process now. I'll let you know what they find!