BMW Z3 Engine Issues, MAF Sensor or Something Else?

Hey there! I have some experience working on BMWs, had a similar issue with my 1998 BMW Z4 last year. Those symptoms sound exactly like what I dealt with, especially the rough idle and poor acceleration. My mechanic diagnosed it as a faulty mass air flow sensor too. They cleaned it first but that didn't solve it, so they replaced it completely. Cost me about 365 Euro all in, including labor. Car's been running like a dream since then. Just to help you better, could you share if you've had your check engine code read? Also, when was the last time you had a tune-up? Knowing these details would help confirm if we're dealing with the same issue. If you'd like any specifics about the repair process or part numbers, let me know. The M52 engines in these cars are quite similar, so what worked for mine might work for yours too.

Thanks for sharing your experience! My Z3 has 145048 KM on the clock and it's been regularly serviced. Had the diagnostics done yesterday, getting error code P0171 (system too lean). Your symptoms match mine exactly. Good to hear replacing the MAF sensor fixed it for you. Did you notice any immediate improvement in performance after the replacement? I'm hoping it's just the MAF sensor and not something more serious. Been driving BMWs for years but this is my first time dealing with this particular issue. Also wondering if you went with OEM parts or aftermarket? I've heard mixed things about aftermarket MAF sensors for these engines.

Hey again! Glad to help out a fellow BMW owner. Yes, the difference after replacing the MAF sensor was like night and day, my Z4 felt completely transformed literally from the first start-up. The engine ran smoother, idle was stable, and that annoying jerking during acceleration completely disappeared. I totally get your concern about OEM vs aftermarket parts. After some research and talking with my mechanic, I went with the OEM Bosch sensor. It was a bit pricier (about 100 Euro more than aftermarket options), but honestly, with these engines, I've learned it's worth spending extra on original parts. That P0171 code is exactly what I got too! Given your mileage and symptoms, it really does sound identical to what I experienced. My mechanic mentioned that MAF sensors typically start acting up around the 140-150K mark on these models, so the timing fits. Quick tip from my experience, while they're replacing the MAF sensor, get them to check and clean the air intake system too. My mechanic did this as part of the service, and it helped ensure everything was working optimally. Trust me, if your symptoms match mine (which they do), replacing the MAF sensor should sort it out. Keep me posted on how it goes!

Thanks so much for all the detailed info! You've really put my mind at ease. After hearing about your experience, I'm going to go ahead and book it in next week to get the MAF sensor replaced. Think I'll follow your advice and go with the OEM Bosch sensor, rather spend a bit more now than risk having to do the job twice with a cheaper part. Really appreciate the tip about checking the air intake system too. I'll definitely mention that to my mechanic when I take it in. Makes sense to do everything while they're in there. It's such a relief to hear your car was transformed after the fix. Can't wait to get mine running properly again, miss that smooth BMW performance! I'll make sure to get back to you with how it turns out. Thanks again for all your help!

Error code 290900 Air system, air to EGR mass flow Plausibility: measured air mass too high compared to calculated air mass What can I do? Agr cooler + agr valve are new

(Translated from German)

Start by checking for any vacuum leaks in the intake system, as these can cause discrepancies in air mass readings. Inspect all hoses and connections for cracks or loose fittings. If everything looks good, consider cleaning the mass air flow sensor, as dirt or debris can affect its accuracy. Let me know how it goes or if you have further questions!