BMW X5 Diesel: Rough Running and Misfire Issues

Hey there! I've got some experience with diesels as I dealt with similar issues on my '04 BMW X3 last year. I'd say I have moderate experience with car maintenance, but I still rely on professionals for complex issues. I faced almost identical symptoms, rough running, misfiring, and that dreaded check engine light. Turned out I had a faulty injector. My trusted mechanic diagnosed it, and they had to replace the defective injection valve. The repair cost me around 515 Euro, but it was worth every penny as it completely solved the issue. Before jumping to conclusions though, could you share more details about your X5? Like when was the last time you had fuel filter changed, or if you've noticed any white smoke from the exhaust? These details would help compare our situations better. Also wondering if you've got a BMW 5 series, they're known for similar issues around that year.

Thanks for your input! My X5 was last serviced about 2 months ago at 191606 KM, and they actually changed the fuel filter then. I haven't noticed any white smoke from the exhaust, but the engine definitely feels more sluggish than usual. The misfiring usually happens when I'm accelerating, especially from a stop. I've heard X5s from this era can have injector issues, but wanted to check if anyone else had confirmed fixes before spending money at the shop. This really helped point me in the right direction, thanks!

Hey again! Thanks for those extra details about your X5. Yeah, this is sounding more and more similar to what I experienced with my X3. The symptoms you're describing, especially the misfiring during acceleration from a stop, that's exactly what I dealt with. Since you mentioned your recent service and fuel filter change, we can probably rule those out. In my case, holding off on the repair only made things worse over time. The sluggishness you're experiencing is another red flag, that's how mine started before it got really bad. After dealing with my injector issue, I learned these BMWs from the mid-2000s are pretty notorious for injection problems. While the quantity drift compensation thing can cause issues, in my experience (and what my mechanic explained), it's usually a sign of a failing injector rather than the root cause. I'd suggest getting it checked soon, my repair bill ended up being higher because I waited too long and it affected other components. The peace of mind after fixing it was totally worth it. Plus, my fuel economy improved significantly after the repair, which was a nice bonus. Let me know what you find out when you get it checked. I'm curious if it turns out to be the same issue as mine!

Really appreciate the detailed feedback! You've convinced me to get it checked out sooner rather than later. Don't want to risk causing more damage by waiting. I'll schedule an appointment with my mechanic tomorrow to have them look at the injectors specifically. The improved fuel economy you mentioned would definitely be a welcome bonus, I've noticed mine has gotten worse lately too. I'll make sure to update once I find out what's causing the problem. Thanks again for sharing your experience, it's been super helpful in narrowing down what might be wrong with my X5!