Audi A4 2.0T Misfire: Common Fixes and Real Costs

I dealt with very similar symptoms on my A6 2.0T from 2014. Having some experience working on these engines, I initially suspected spark plugs or a vacuum leak, but it turned out to be more complex. After taking it to my workshop, they diagnosed a leak in the exhaust system that was causing irregular oxygen sensor readings. This was triggering the rough idle and inconsistent acceleration you described. The oxygen sensor was getting false readings, making the engine run rich at times. The complete repair involved: Fixing the exhaust leak, Cleaning the air filter system, Testing all spark plugs, Recalibrating the oxygen sensor Total cost was 265 Euro and it completely resolved the jerking and rough idle issues. To better assist with your case, could you provide: Build year of your A4, When was the last time spark plugs were replaced, Are you noticing any unusual exhaust sounds, Does the check engine light flash or stay constant, Any recent maintenance history This information would help determine if youre dealing with a similar exhaust system issue or something different.

Just had the same symptoms with my 2014 A4 at 12777KM. The rough idle and engine misfire turned out to be caused by dirty fuel injectors. After a thorough fuel system cleaning and new air filter installation, the problems cleared up. The oxygen sensor readings returned to normal and the check engine light went off. Total repair cost was 180 Euro. Make sure to also check your coil packs, they can cause similar symptoms and are a common issue on these engines.

Thanks for the update on your A4! This matches my experience with my A6, these engines are quite sensitive to fuel system issues. After fixing my exhaust leak and oxygen sensor problem that I mentioned earlier, I also had the fuel injectors cleaned as preventive maintenance. A dirty fuel delivery system can definitely cause those erratic oxygen sensor readings we both experienced. The combination of bad readings and uneven fuel spray creates that characteristic jerking during acceleration. Since both our cars are 2014 models, its worth mentioning that its also a good time to check the ignition coils if you havent already. The original coils tend to start failing around this mileage, and a failing coil pack mimics fuel injector symptoms with misfires and rough idle. On my A6, I now do fuel system cleaning every 30000km as preventive maintenance. The crankshaft sensor and timing belt are next on my maintenance schedule, just to stay ahead of potential issues. Its much cheaper than waiting for problems to develop. Good to hear you got it sorted for 180 Euro, thats actually less than what I paid for my repair!

Thanks for the input. I got my A4 fixed yesterday and wanted to share the outcome since it might help others. The symptoms I described in my initial post, engine misfire, jerking, and rough idle, were indeed caused by failing fuel injectors. A thorough fuel system cleaning and new air filter installation fixed everything. The oxygen sensor readings are now back to normal and the check engine light has turned off. The repair cost came to 180 Euro, which seems reasonable considering the alternative of replacing parts unnecessarily. For anyone experiencing similar issues, make sure to have your ignition coils checked too, the mechanic mentioned they often cause identical symptoms and frequently need replacement in these engines. Regular fuel system cleaning is now part of my maintenance schedule to prevent future issues. Just wanted to close this thread and thank those who replied with advice. Your suggestions helped me better understand the problem and discuss it more effectively with my mechanic.