BMW X1 Engine Running Rough, Lean Mixture Issue?

Hey there! I had a similar issue with my 2011 BMW X3 last year. I have some experience working on cars, but mostly basic maintenance stuff. The symptoms you described sound exactly like what I experienced. My car was sluggish, had rough idling, and the check engine light was constantly on. Turned out one of the fuel injectors was faulty, causing uneven fuel delivery to the engine. Had to get it replaced at my trusted workshop. Bill came to around 515 Euro, not cheap, but it solved the issue completely. Before giving more specific advice, could you share: How many miles/kilometers on your X1? Are you getting any specific error codes? Does it run worse when the engine is cold or warm? Just want to make sure we're dealing with the same problem here, since BMWs can be tricky. I've owned both the X3 and a 3 Series, and they sometimes have similar fuel system issues.

Thanks for your detailed response! Mine has 54604 KM and just had its service last month. When cold, it definitely runs worse and takes a while to smooth out. I haven't checked the error codes yet, but planning to get those read tomorrow. You mentioning the fuel injector issue is really helpful, the symptoms do sound very similar. The rough idling and jerking during acceleration is exactly what I'm experiencing. Will definitely have the mechanic check the injectors when I take it in. Really hoping it won't cost me as much as yours did!

Hey again! You know, after reading about your cold start issues, I'm even more convinced we had the same problem. My X3 had about 58000 KM when the injector issue started, so pretty similar mileage to yours. Just wanted to add, when my injector was failing, I noticed the cold starts were particularly bad in the morning. The engine would shake quite a bit for the first few minutes, right? And that jerking during acceleration was super annoying, especially when trying to merge onto highways. Quick tip though, before you spend big money on new injectors like I did, ask your mechanic to check the fuel pressure and do a proper injector cleaning first. I wish I'd known this earlier, but sometimes carbon buildup can cause similar symptoms, and a good cleaning might sort it out for much less than a full replacement. Also, after I got mine fixed, I started using higher quality fuel and fuel system cleaner every few months. Haven't had any issues since then. Let us know what the error codes say, that'll definitely help narrow things down. Hope you get it sorted for less than I did!

Thanks so much for all the great advice! You're absolutely right about the morning cold starts, it shakes like crazy for the first few minutes. That's such a helpful tip about getting the injectors cleaned first before jumping into replacement. I'll definitely mention that to my mechanic tomorrow. Been using regular fuel all this time, but will switch to premium and try those fuel system cleaners you mentioned once this is fixed. Really appreciate you taking the time to share your experience, saved me from walking into the workshop completely clueless! Will update the thread once I get the error codes and find out what's actually wrong. Thanks again for all your help!