BMW X1 Rough Idle and Stalling, Fuel System Issues?

Hey there! I had a very similar issue with my 2017 BMW X3 last year after changing the fuel filter. The symptoms match exactly what you're describing, rough idle, stalling, and power issues. Initially thought it was the fuel pressure regulator too. Turned out there was an error in the ECU that needed to be cleared and recalibrated after the filter change. Took it to my regular workshop, and they sorted it out in about an hour. Cost me 45 Euro, pretty reasonable for the peace of mind. Before I can give more specific advice, could you share: Have you recently had any work done on the fuel system? What error code is showing up? Does the problem get worse when the engine is warm or cold? Also had a 320i in the family, and these BMWs can be sensitive to fuel system changes. Better to get it checked soon to prevent any bigger issues.

Hi! Thanks for chiming in with your experience. I should mention my X1 has 35424 KM on the clock and just had its service last month. Actually, no recent work was done on the fuel system. The error code showing is P0171 (system too lean). The issue seems more pronounced when the engine is cold, especially during the first 10-15 minutes of driving. After that, it's still there but slightly less noticeable. Really appreciate the tip about the ECU recalibration, that's definitely worth checking out. Did you notice any other warning lights besides the check engine when you had your issue?

Hey again! Thanks for the additional info about your X1. You know what? When you mentioned the P0171 code and the cold start symptoms, it actually reminds me even more of what happened with my X3. I also had that same code pop up! In my case, though, I only had the check engine light, no other warning lights. After my earlier comment about the ECU, I had another issue a few months later that turned out to be a faulty Mass Air Flow (MAF) sensor. The symptoms were nearly identical to what you're describing, especially that cold start roughness. The lean condition code combined with the cold start issues is pretty typical of a MAF sensor problem. I paid about 230 for the part and labor, and it fixed the issue completely. Much cheaper than I expected, honestly. Quick tip from my experience, before replacing any parts, try cleaning the current MAF sensor with proper MAF cleaner spray. Sometimes that's all it needs, and it saved me money on my old 320i before I got the X3. Let me know what you find out, really curious if it's the same issue as mine!

Thanks so much for the detailed follow-up! That's really interesting about the MAF sensor, it makes a lot of sense given my symptoms. Plus, it's way more affordable than what I was fearing with the fuel pressure regulator. I'll definitely try cleaning the MAF sensor first, great tip about using the proper cleaner spray. I actually have a mechanic friend who might be able to help me with that this weekend. If that doesn't work, at least I know replacing it won't break the bank. It's such a relief to hear from someone who's dealt with the same issue. Was getting worried it might be something major! I'll update once I've had it checked out. Really appreciate all your help and sharing your experience with both your X3 and 320i. Sometimes these BMWs can be tricky to diagnose! Thanks again for taking the time to help me out. You've given me a solid direction to start with.