RS6 MAF Sensor Failure Causing Stalling and Poor MPG

Had the exact same symptoms on my 2012 S6 last season. The engine stalling at idle and irregular performance were clear signs of sensor failure. Initially thought it was just a dirty air filter, but the check engine light and diagnostic confirmed a faulty MAF sensor. The repair was straightforward but crucial. A faulty MAF sends incorrect air-fuel mixture data to the ECU, causing performance decline and the symptoms you describe. The smoke under acceleration is typical of a rich fuel mixture caused by MAF misreadings. The fix required replacing the entire MAF sensor unit. This is not something to postpone, running with a bad MAF can damage your catalytic converter due to improper fuel mixture. The repair took about 1 hour at the shop. The car ran noticeably smoother after replacement, idle stabilized, and fuel economy returned to normal. Would recommend getting it checked soon to prevent potential engine damage. These sensors typically fail around the mileage you mentioned.

Thanks for the detailed response about the MAF sensor replacement. My Audi is running much better now after getting it fixed. The air-fuel ratio is back to normal and the engine stalling completely stopped. The performance decline and smoke issues are also gone. Did you happen to remember the total cost for your repair? Also curious if you encountered any other issues with the air intake system since the replacement? Want to know what to watch out for going forward.

Thanks for the follow-up. The MAF sensor repair on my S6 cost 365 Euro including parts and labor. Since the replacement, the car has performed flawlessly with no air-fuel ratio issues or engine stalling problems. The fuel economy returned to normal levels immediately after the fix. After getting the mass air flow meter replaced, I started doing regular air filter checks every service interval to prevent any future sensor failure. A clean air filter helps maintain proper airflow readings and sensor longevity. In the year since the repair, I have not experienced any other air intake system issues. The engine runs smooth, maintains steady idle, and the check engine light has stayed off. Just make sure to use quality air filters and keep up with regular maintenance to avoid similar problems in the future. The repair cost was worth every cent considering how it resolved all the performance issues and prevented potential long-term engine damage.

Thanks for the advice. I took my RS6 to the repair shop last week and they confirmed the MAF sensor was faulty. The final bill came to 420 Euro which included parts and labor. The mechanic also cleaned the air filter housing while doing the work. What a difference in performance now. The fuel economy has improved significantly and the engine runs perfectly smooth at idle. No more smoke under acceleration and the check engine light is finally off. The air-fuel ratio readings are back to normal ranges according to my scan tool. The mechanic mentioned I should change the air filter more frequently to protect the new sensor. He showed me how much debris had built up in the housing, which likely contributed to the sensor failure. Going to stick to a strict maintenance schedule from now on to avoid these issues. Really glad I got this sorted quickly before it could cause any serious engine damage. The car feels like new again.