BMW X6 3.0L Performance Issues, Multiple Symptoms Help

Hi there! I'm a hobby mechanic with some experience working on BMWs. Actually had a very similar issue with my 2006 BMW X5 3.0i last year. The symptoms you describe sound exactly like what I experienced, my car was also running rough and had poor acceleration. Turned out one of the fuel injectors was faulty, causing uneven fuel delivery. Took it to my regular workshop and they diagnosed it through testing injection pressure and doing a smoke test. Total repair with parts and labor came to 515 Euro, they replaced the defective injector. Before you proceed though, could you share: Current mileage? Any recent maintenance done? Any specific error codes? Also, while you have an X6, I'd recommend checking out common issues with the X3 from that era too, they share similar fuel system components. Let me know these details and I can provide more specific guidance based on my experience.

Thanks for the detailed response! My X6 just had its latest service done but the issues started shortly after. Currently at 91539 KM on the clock. I actually got the error codes checked, showing P0171 and P0174 (system too lean, both banks). Makes sense with the symptoms you mentioned about the fuel injectors. Good to know about your experience with a similar issue. Did you notice any improvement in fuel economy after fixing the injector? Think I'll get the injection pressure tested at my mechanic's this week. Really hoping it's just an injector and not something more serious with the fuel system. These repairs can get pretty expensive with BMWs!

Hey again! Yeah, after fixing that injector on my X5, I definitely noticed some improvements in fuel economy, went from burning through a tank way too quick to getting much better mileage. Those error codes you're getting are exactly what I had too, so I'm pretty confident you're dealing with a similar issue. Just a heads up though, when they were working on my car, they found that the bad injector had actually caused some carbon buildup in that cylinder. Had them do a proper clean while they were in there. Bit more expensive but totally worth it for the smooth running after. About those lean codes on both banks, that's interesting because with my X5, it started with just one bank throwing codes, then spread to both. You might want to have them check your fuel pressure regulator too. Mine was actually showing signs of wear, but luckily didn't need replacing at the time. Since you mentioned getting it serviced recently, did they change the fuel filter? Sometimes a clogged filter can cause similar symptoms, and it's way cheaper to fix than injectors. Worth checking before diving into the more expensive stuff. Let us know what your mechanic finds, always good to share these experiences for other BMW owners dealing with similar issues!

Thanks so much for all that extra detail! Really helpful to hear about the carbon buildup issue too, definitely going to mention that to my mechanic when I take it in. Good thinking about the fuel filter, I'll check my service records, but I don't remember it being changed recently. I've already booked the car in for tomorrow morning to get everything checked out. Will make sure they look at the fuel pressure regulator as well since you mentioned that could be related. Better to catch any potential issues now rather than wait for more problems to develop. Really appreciate you taking the time to share your experience, it's given me a much better idea of what to expect and what to ask the mechanic to check. Nothing worse than going in blind with these kinds of issues! I'll update the forum once I get the diagnosis and repair done, might help someone else down the line. Thanks again for all your help!