BMW Z4 Multiple Issues, Fuel System Crisis Alert

Hey there! I have some experience working on cars as a hobby mechanic. I actually faced very similar symptoms with my 2020 BMW M240i last year. The symptoms were almost identical, rough idle, jerking, and that annoying check engine light. Turned out one of the fuel injectors was faulty, causing all sorts of fuel mixture problems. Took it to my regular workshop and they diagnosed it with their computer system. Had to replace one injector, cost me around 515 Euro for parts and labor. Since then, car's been running smooth as butter. Worth every penny to get it fixed properly. Before I share more details about my experience, what's your exact engine variant on the Z4? Also, have you noticed any specific conditions when these symptoms get worse (like cold starts or after refueling)? This could help narrow down if we're dealing with the same issue.

Thanks for sharing your experience! My Z4's been really well maintained with its last service just done, but these issues started popping up recently at 131135 KM. I've got the 3.0L gasoline engine variant. Actually, thinking about it, the symptoms do get worse during cold starts and it takes longer than usual to stabilize. The jerking is especially noticeable when I'm trying to accelerate from low speeds. Hearing about your injector issue is helpful, the symptoms do sound really similar to what I'm experiencing. That repair cost doesn't sound too bad considering how much trouble it's causing. Did your car also have that slight hesitation between gear shifts while the problem was ongoing? Just trying to compare notes here.

Hey again! Yeah, I can totally relate to what you're describing with those additional details about the hesitation between gear shifts. My M240i had that exact same annoying hesitation, it was super frustrating, especially when trying to get up to highway speeds. Actually, when you mention the cold start issues, that's exactly how mine started too. Used to take forever to settle into a smooth idle in the mornings. Mine was at about 125000 KM when these problems showed up, so pretty close to your mileage. Since we've got similar engines in our BMWs (mine's also the 3.0L), I'm even more convinced now we're looking at the same injector issue. After my repair, that hesitation between shifts completely disappeared along with all the other symptoms. Really transformed the car back to its smooth-running self. Just a heads up, when they were fixing mine, they found that the faulty injector had actually started affecting the O2 sensor readings too. Might be worth asking your workshop to check that while they're at it. Didn't cost much extra to test, and it's good peace of mind. Let me know how it goes when you get it checked out. Really curious to see if it's the same problem I had.

Thanks so much for all the detailed info! It's really reassuring to hear from someone who's dealt with such similar issues. The fact that your car had the same symptoms, especially that gear shift hesitation and cold start problems, at almost the same mileage makes me feel better about the whole situation. I've just booked my Z4 in for next week. I'll definitely mention the injector issue and ask them to check the O2 sensors too, that's a great tip. The repair cost you mentioned seems reasonable, especially if it fixes all these annoying problems. Will definitely keep you posted on what they find. Really appreciate you taking the time to share your experience. It's helped me feel more confident about what might be wrong instead of just guessing. At least now I won't be going into the workshop completely blind!