BMW X5: Drop in Power and Rough Idle, Fuel System Issue?

Hey there! I had some experience with my 2003 BMW X3 (3.0L gas engine) with very similar symptoms last year. I'd say I have low experience with car repairs, but I try to learn from each issue. After changing the fuel filter myself (bad idea in hindsight), I got similar problems, check engine light, rough idle, and poor acceleration. Turned out there was an error in the fuel pressure system that needed to be reset. Took it to my workshop, and they had to clear the error codes and recalibrate the fuel system. Pretty straightforward fix, cost me about 45 Euro. Could definitely be your fuel pressure regulator, but to help better, could you share: Any recent maintenance you've done? Does it happen more when the engine is cold or warm? Any specific error codes showing up? Also, if you're having trouble with a BMW X5, you might want to check the fuel pressure sensor too, they can act up on these models.

Thanks for sharing your experience! Just had my service done 2 weeks ago at 104779 KM, and these issues started popping up right after. The problems are definitely worse when the engine's cold, especially in the morning. Haven't checked the error codes yet, but planning to get them read tomorrow. The thing is, I'm a bit hesitant about DIY fixes since my last attempt at changing the air filter turned into a bigger headache than expected. Your mention of the fuel pressure sensor is interesting, that might explain why the issues seem more noticeable during cold starts. Did your mechanic mention anything specific about detection rates for faulty sensors versus regulators? Really appreciate the input!

Hey again! Yeah, after my experience with the X3, I totally get your hesitation about DIY fixes! When my mechanic worked on my car, he actually gave me some interesting insights about the fuel pressure system. He mentioned that faulty sensors are way more common than bad regulators on these engines, something like 3 or 4 times more likely to be the culprit. Speaking of cold starts, that's exactly what happened with mine. It would act up really badly in the morning, then sort of "settle down" once warmed up (though still not running great). The fact that your issues started right after a service is really interesting, reminds me of my situation with the fuel filter change. Sometimes when they work on one part, it can upset the delicate balance of these systems. I learned my lesson about trying to fix complex fuel system issues myself, these BMWs are pretty sophisticated and one wrong move can cause all sorts of chaos. Definitely get those error codes read first. My mechanic showed me that the codes can really point you in the right direction between sensor and regulator issues. Quick tip though, if your codes show anything like P0171 or P0174 (those were mine), it's often linked to the fuel pressure sensor rather than the regulator. Worth keeping in mind when you get them checked tomorrow. Let me know what codes you get, I'm curious if you're dealing with the same gremlins I had!

Thanks so much for all that detailed info! That's super helpful, especially about the sensor being more likely to fail than the regulator. My gut feeling is leaning toward the sensor now, given how similar our symptoms are. It's pretty reassuring to hear your experience was fixable without breaking the bank. I'll definitely get those codes checked tomorrow and keep an eye out for the P0171/P0174 you mentioned. You're right about these BMWs being complex, lesson learned about trying to save money with DIY fixes! Think I'll stick to letting the pros handle it this time. Really appreciate you taking the time to share your experience. I'll let you know what the codes show up once I get them checked. Thanks again for all the help!