S6 Bucking + Power Loss Points to MAF Sensor Issues

Had nearly identical symptoms with my 2020 Audi S4. The lean condition was causing significant performance issues. After running diagnostics, it turned out the fuel injectors were failing, causing uneven fuel delivery to the cylinders. The air-fuel ratio was way off, leading to misfires and that bucking sensation during acceleration. This also triggered the oxygen sensor to report lean conditions. While the mass air flow sensor was initially suspected, the root cause was definitely the injectors. This is a serious repair that requires proper diagnostic equipment and expertise. The injectors need precise calibration after replacement to ensure optimal fuel delivery through the intake manifold. Poor injector performance can eventually damage the catalytic converter if left unaddressed. When these symptoms appeared on my S4, the car needed multiple injectors replaced. The repair requires specialized tools and proper testing equipment to ensure everything is working correctly with the engine management system. For this type of issue, look for shops that specialize in VAG vehicles and have factory diagnostic equipment. Ask them about their experience specifically with direct injection systems on modern Audi engines.

Thanks for sharing your experience. Ive been going through something similar with my S6, sounds exactly like what you described with the fuel injectors failing. The lean condition was giving me all sorts of headaches. Wanted to ask, do you remember roughly what the repair cost came to? Also curious if youve had any other issues pop up since getting the injectors replaced. Im particularly concerned about the throttle body and EGR valve since they can sometimes act up after injector problems. The intake manifold on mine is also making some odd noises now, so trying to figure out if thats related or a separate issue I need to watch out for.

The total repair bill came to 515 Euro for replacing the faulty injection valve. Since getting it fixed, the lean condition has completely cleared up and the engine is running smoothly again. The check engine light disappeared and that frustrating power loss is gone. I havent experienced any issues with the throttle body or EGR valve in the months following the repair. The engine management system is now showing proper fuel trim values and the oxygen sensor readings are exactly where they should be. Regarding your intake manifold noise, this wasnt something I encountered after my injector repair. I would have the shop check this separately since unusual sounds from that area could indicate a different issue. Best to address it early before it potentially affects other components. The investment in fixing the injector was worth it to restore proper engine performance and prevent more expensive repairs down the line. Just make sure whoever does the work properly calibrates the new injector to match the engines specifications.

Thanks for the input. I finally got the car looked at and wanted to share my experience in case someone else runs into this. Took it to a specialized shop that diagnosed the problem using proper diagnostic equipment. Just as suspected, multiple fuel injectors were failing. The check engine light was definitely trying to tell me something. The total repair came to 1250 Euro for replacing three injectors. While at the shop, they also cleaned the throttle body and checked the mass air flow sensor, which turned out to be fine. That grinding noise from the intake manifold ended up being unrelated, just a loose heat shield that they tightened up at no extra charge. The car runs like new now. No more bucking during acceleration, power is fully restored, and fuel economy has actually improved. The spark plugs also got replaced as a preventive measure since they were getting close to their service interval anyway. Looking back, getting it fixed right away was the smart move. Could have caused way more damage if I kept driving it with those failing injectors.