Problems with BMW Z4 2009: Black smoke, loss of power and increased fuel consumption - Possible lambda sensor problems?

Hey, this sounds very similar to what I went through with my 2006 BMW M3. At my last garage visit, the problem was a rather clogged mass airflow sensor. It caused similar symptoms for me: rough running, higher fuel consumption and that jerking under acceleration. The good news in your case is that it shouldn't be serious and is relatively easy to fix. The lambda sensor could be the problem, as you suspect, but it could also be that you just need to clean or replace the mass air flow sensor. Don't worry, it will be fine.

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Hey, thanks for the quick and helpful reply! Do you remember roughly what you paid for the repair back then? And have you had any additional problems or similar with your M3 since then? I really hope it's just the mass airflow sensor and not something more serious... Thanks again for the info!

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I have to say that since the mechanic replaced the lambda sensor, the problem has not reappeared. The whole thing cost me around €375. The ceramic inside the lambda sensor was defective. I certainly hope I don't have to have problems like this again with my Audi A3, it's a bit annoying. Don't get too involved! It's not a problem that can't be solved. Good luck!

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Hi, I'll jump in quickly too. The situation you describe does indeed suggest that there is a problem with the lambda sensor. I had a similar problem with my old Mercedes CLK. After almost 140,000 km, I noticed similar symptoms to yours. It turned out that the lambda sensor had aged. After replacing it, the car ran like new again. It is obvious that your lambda sensor has now also aged due to the high mileage of more than 120,000 km. The costs can of course vary depending on the model and workshop, but your outlay should be around €300 if the lambda sensor needs replacing. All the best and don't let it get you down, you can do it!

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Thanks to everyone for the helpful replies and encouragement! I'm relieved that you guys think it's probably nothing too serious. I took my BMW to the garage this morning. The mechanic looked it all over and - just as you suspected - the problem was indeed the mass airflow sensor AND the lambda sensor. They both had to be cleaned and replaced, but the repair actually only amounted to about €575. Since then the car has been running like a dream again, no more juddering and high fuel consumption! I'm really relieved and happy that this was solved so easily. Thank you again for your support, without you I would certainly have paid more. All the best and best wishes!

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I have changed the lambda but the indicator light keeps coming on ?

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If the check engine light is still on after replacing the lambda sensor, it could be due to a few reasons. First, ensure that the error codes were cleared from the car's computer after the replacement. If the light persists, there might be another issue such as a faulty connection, another sensor problem, or an exhaust leak. I recommend checking for any additional error codes with an OBD-II scanner to pinpoint the exact issue. Let me know how it goes or if you have further questions!