BMW X5 Running Rich: Help Diagnose Engine Power Loss

Hey there! I have some experience working on cars, and this sounds very familiar. I had a similar issue with my 2003 BMW X3 3.0i last year. My car showed exactly these symptoms, rough running, drop in power, and excessive fuel consumption. After taking it to my regular workshop, they diagnosed a faulty fuel injector. One of the injectors was stuck open, causing too much fuel to enter the cylinder. Got it fixed with a new injector, and it set me back about 515 Euro, but the car's been running like new since then. Before jumping to conclusions though, could you share: Are you getting any specific error codes? Does it happen more during cold starts or when the engine's warm? Have you noticed any black smoke from the exhaust? By the way, I also own a 525i, and these BMWs are generally solid, but injection systems can be tricky. Let me know these details, and I might be able to help further.

Thanks for the detailed response! I've got 151951 KM on my X5, and it was just serviced last month. The symptoms are definitely worse during cold starts, and yes, I've noticed darker smoke than usual from the exhaust. Haven't pulled the error codes yet, but planning to do that tomorrow. The jerking is more noticeable when I'm cruising at steady speeds and then try to accelerate. I'll definitely get those injectors checked out based on your experience. After reading your comment, I remembered the mechanic mentioning something about the injection system during my last service, but I didn't think much of it then. Probably should have paid more attention! Did you notice any warning signs before your injector completely failed? Just trying to understand if I should get this sorted immediately or if I can drive it for another week until my regular mechanic is back from vacation.

Hey again! Thanks for the follow-up. Since you asked about warning signs, yes, I definitely had some before my injector completely failed on my X3. Actually, your symptoms sound nearly identical to what I experienced. In my case, the first sign was that slight hesitation during acceleration, especially when the engine was cold. Then it got progressively worse over about two weeks, the jerking became more pronounced, and fuel consumption went through the roof. I was getting about 25% less mileage than usual. Looking back, I really wish I hadn't driven it for those two weeks. The faulty injector was dumping excess fuel into the cylinder, which ended up washing away some of the oil film on the cylinder walls. Had to get the cylinder walls checked for scoring too, which added to the repair cost. Given what you're describing, especially that dark smoke and the cold start issues, I'd strongly advise against waiting a week. These symptoms are pretty much textbook injector problems, and continuing to drive could lead to more expensive repairs. When my injector failed, I was lucky it didn't cause more damage to the engine. My X3's running great now after the fix, but I learned my lesson about ignoring these kinds of symptoms. Better to deal with one faulty injector than risk engine damage. Would you like me to recommend some things you can check while waiting to see your mechanic?

Thanks so much for all this info, it's been super helpful! You've definitely convinced me not to wait on this repair. Those extra costs you mentioned from cylinder wall damage are exactly what I want to avoid. I just called around and found another reputable BMW specialist who can look at it tomorrow morning. Figure it's better to pay for the repair now than risk more expensive engine damage later. The symptoms are way too similar to what you experienced to ignore. Really appreciate you sharing your experience with the X3. Especially glad you mentioned the bit about how quickly it progressed from minor issues to potentially serious damage. Looking back, I've probably been noticing these symptoms for about a week but kept putting off dealing with them. While I'm disappointed about having to get this fixed right away (definitely wasn't in my budget this month!), at least I know what I'm likely dealing with. Will update you once I get the diagnosis, hoping it's just an injector and nothing more serious. Thanks again for taking the time to help me out with this!