BMW MAF Sensor Symptoms: Expert Fix Guide and Costs

I had almost identical issues with my 2020 BMW M340i last month. The symptoms matched yours exactly, rough idle, sluggish acceleration, and terrible fuel economy. The check engine light came on during highway driving. Got it checked at the garage, and yes, it was definitely the MAF sensor. The mechanic showed me how dirty and contaminated it was. The repair wasn't too complex, they cleaned the sensor first, but it didn't solve the problem completely. Ended up needing a new MAF sensor. It's not a major repair, but it's crucial since the MAF sensor controls the air-fuel mixture. Running the car with a faulty MAF can damage other components over time. In my case, the whole job took about an hour and a half. Just make sure you get genuine BMW parts and have it done by someone who knows these engines. Mine's been running perfectly since the replacement, better acceleration, smooth idle, and back to normal fuel consumption.

Thanks so much for sharing your experience! This sounds exactly like what I'm dealing with. Really helpful to know it was just the MAF sensor and nothing more serious. Do you remember roughly how much the repair cost you? Also, has everything been running smoothly since then or have you noticed any other issues pop up?

Hey there! Glad to help follow up on this. Yeah, I got the MAF sensor replaced about 6 weeks ago and it cost me 365 €, not cheap, but worth every penny. The mechanic diagnosed it straight away as a defective Mass air flow meter and they fixed it properly. I'm happy to report my M340i has been running like an absolute dream since the repair. The idle is buttery smooth now, acceleration is back to being properly sporty, and fuel consumption is normal again. No other issues have shown up at all. Just make sure you get it sorted soon, running with a faulty MAF sensor isn't great for the engine in the long run. Trust me, you'll notice the difference immediately after it's fixed. My car feels like new again! Let me know if you need any other info about the repair.

Just got back from the mechanic and wanted to update you! You were spot on with everything. Took your advice and got it checked right away. The mechanic found the faulty MAF sensor, and like your case, cleaning didn't solve it completely. Had to get a new one installed. Cost me about the same as yours, and honestly, what a difference! My car's running incredibly smooth now, no more rough idling or sluggish acceleration. Fuel consumption's back to normal too. The mechanic was really professional, showed me the old sensor and explained everything. Thanks again for your help. You saved me from a lot of worry and potentially more expensive repairs down the line. Really appreciate you sharing your experience, made me feel much more confident about getting it fixed.