BMW X4 Diesel Misfires: Quantity Drift Issues?

Hey there! I have some experience working on cars, and I went through something very similar with my 2012 BMW X3 diesel last year. The symptoms were exactly like what you're describing, misfiring, rough running, and that annoying check engine light. Turned out one of my injectors was faulty. Had to take it to my regular workshop where they diagnosed and replaced it. The whole thing set me back about 515 Euro, but it fixed the issue completely. No more problems since then. By the way, my has an X5 from around the same time, and these injection issues aren't uncommon in these engines. Could you share more details about when exactly these symptoms occur? Like, does it happen more when the engine is cold or warm? This would help me understand if you're dealing with the same problem I had.

Thanks for sharing your experience! My X4 is actually running pretty well otherwise, with 19899 KM since new and I just had it serviced last month. The misfiring usually happens when I'm cruising at steady speeds, and it's definitely more noticeable when the engine is warm. Been dealing with this for about two weeks now. What you mentioned about the injector makes a lot of sense, I'm getting similar symptoms. Did you notice any decrease in fuel efficiency before you got yours fixed? Really hoping it won't cost me too much to sort out.

Yeah, I remember dealing with this on my X3! And what you're describing about the misfiring during steady cruising and when the engine's warm, that's exactly how mine started acting up. Actually, now that you mention fuel efficiency, yes! I definitely noticed my fuel consumption went up by about 15-20% before I got it fixed. I kept track because I was doing similar commutes every day, and the tank just wasn't lasting as long as usual. One thing I didn't mention in my first reply, before I got the injector replaced, I tried cleaning the fuel system thinking it might be a cheaper fix, but that didn't solve it. So if you're thinking about trying that route first, I'd say just go straight for the proper diagnosis. Could save you some money in the long run. Since your X4 is pretty low mileage and recently serviced, I'd definitely get this checked out soon. These symptoms typically don't go away on their own, and running it with a faulty injector could potentially cause more issues. My mechanic explained that modern diesel engines are pretty sensitive to injection problems. Let me know what you find out, curious to see if it's the same issue I had with mine!

Thanks for the detailed follow-up! That's really helpful info about the fuel consumption, I've actually started noticing the same thing with my tank not lasting as long as usual. Good to know about the fuel system cleaning too, I was actually considering trying that first, so you probably just saved me some time and money there! I've gone ahead and booked it in at my regular workshop for next week. You're right about not wanting to risk any additional damage, especially since these diesel engines can be so sensitive. The symptoms match up so closely with what you experienced that I'm pretty convinced it's an injector issue now. I'll definitely update you once I get it diagnosed and fixed. Really appreciate you sharing your experience, it's made me feel a lot more confident about what I'm dealing with here!