BMW X6 Misfiring Mystery: Help Diagnose Engine Issues

Hey there! I have some experience working on cars, and I went through something really similar with my 2010 BMW X5 3.0i last year. Those symptoms sound exactly like what I experienced, my car was misfiring badly and had zero power when accelerating. Turned out I had a faulty fuel injector. Had to take it to my trusted workshop where they diagnosed and replaced the defective injector. The whole thing, including parts and labor, set me back about 515 Euro, but it fixed the issue completely. The car's been running smooth as silk since then. I also own a BMW 5 Series, and these engines are pretty similar in design. But before jumping to conclusions, could you share: Any weird sounds when this happens? Does it get worse when the engine's warm or cold? Any other warning lights besides the CEL? This info would help pinpoint if you're dealing with the same problem I had.

Just had my latest service done recently, but started experiencing these exact same symptoms with my X6 too (28432 KM on the clock). Your fuel injector theory makes a lot of sense, especially since I'm getting similar behavior. The engine makes a subtle knocking sound when accelerating, and it definitely gets worse after the engine warms up. No other warning lights besides the CEL though. Going to have it checked out this week since it's really affecting performance. Thanks for sharing your experience, really helps narrow down the possible causes. Did you notice any improvement in fuel economy after getting the injector replaced?

Hey again! Thanks for those extra details about your X6. Yeah, that knocking sound during acceleration, that's exactly what mine was doing too! And the fact it gets worse when warm matches my experience perfectly. After I got the injector replaced, the difference in fuel economy was actually pretty noticeable. I was burning through fuel like crazy before the fix, probably getting about 20-25% worse mileage than normal. Once the new injector was in, it went back to what it should be. Just a heads up though, while you're getting it checked, might be worth having them look at the spark plugs too. In my case, the faulty injector had caused some carbon buildup on the plugs. My mechanic recommended changing them at the same time since they were already going to be accessing that area. Saved me some labor costs in the long run. Quick question, have you noticed any black smoke from the exhaust? That was another symptom I had that I forgot to mention earlier. If you're seeing that too, it's another sign pointing to injector issues. Keep me posted on what your mechanic finds. Always interested to hear how these things turn out, especially since we're dealing with such similar cars.

Thanks for following up! Actually yes, now that you mention it, I have noticed some dark smoke occasionally when I accelerate hard. That definitely adds to the evidence pointing toward injector problems. Really appreciate the tip about the spark plugs too, makes total sense to change them while they're in there. The fuel consumption thing is interesting because I've definitely been filling up more frequently lately, but I hadn't connected it to this issue. Looking at my fuel logs, I'm probably burning about 25% more fuel than usual too. I've got an appointment booked for tomorrow morning, and I'll make sure to mention everything we've discussed. It's such a relief to hear from someone who's dealt with the same problem. Will let you know what they find, but I'm betting you're right about the injector. Thanks again for all the help!