RS3 MAF Sensor Symptoms: Stalling and Heavy Fuel Use

Had similar symptoms on a 2015 S3 last month. The mass air flow sensor failure caused the engine to run rich, leading to excessive fuel consumption and black smoke. The check engine light triggered due to incorrect air-fuel mixture readings. First checked the air filter, which was clean. Then tested the mass air flow sensor output with a diagnostic tool, confirming inconsistent readings. The faulty sensor was causing engine stalling at idle and rough acceleration. The repair required replacing the mass air flow sensor and cleaning the air intake system. This was a moderate repair that took about 2 hours at the shop. Not a major mechanical issue, but definitely needs proper attention to prevent potential engine damage. Quick tip: Before heading to the shop, check if there are any loose connections around the air intake or visible damage to the sensor wiring. Sometimes a thorough cleaning of the mass air flow sensor can resolve similar symptoms, but in this case, full replacement was necessary. Would recommend getting it checked soon, as continuing to drive with incorrect air-fuel ratios can lead to more serious engine problems over time.

Thanks for sharing your experience. The symptoms you described match exactly what I was dealing with on my RS3. I went ahead and had it fixed at a shop last week since the engine stalling was getting worse, especially during cold starts. Really helpful to know about checking the air intake system and connections first. Just curious, do you remember roughly what you paid for the full repair? Also, has everything been running smoothly since the sensor replacement or did you notice any other issues pop up?

Since getting the mass air flow sensor replaced on my S3, the engine has been running perfectly. The repair cost came to 365 Euro, which included diagnostic work and cleaning of the entire air intake system. The performance decline and fuel economy issues completely disappeared after fixing the faulty sensor. No more stalling at idle or rich air-fuel ratio problems. The black smoke is gone and cold starts are smooth again. A properly functioning mass air flow sensor makes a huge difference in how the engine runs. The air filter was also replaced during service as a preventive measure, though it turned out the main culprit was definitely the defective sensor. Just keep an eye on your check engine light over the next few weeks. In my case, it never came back on and fuel consumption returned to normal levels right after the repair.

After taking it to the shop, they confirmed it was indeed the mass air flow sensor causing all the trouble. The total repair came to 410 Euro, bit more than yours but included a full system cleaning and new air filter. The mechanic was actually great this time, showed me the old sensor and explained how it was making the engine run too rich. Really different experience from my last repair nightmare. Been driving it for about a week now and what a difference. No more check engine light, fuel economy is back to normal, and the engine runs smooth as silk. Cold starts are perfect and that worrying smoke is completely gone. Best decision was not waiting longer to get it fixed. The stalling was starting to make me nervous about driving it, especially in traffic. Definitely learned my lesson about acting quickly when these symptoms show up.