Audi S3 Misfire Issues Causing Power Loss and Jerking

I experienced similar symptoms with my 2007 Audi A4 2.0T. The rough idle and engine misfiring turned out to be failing fuel injectors. The symptoms started with occasional jerking during acceleration, and the engine would stumble especially when cold. The cylinder misfire was confirmed through diagnostic testing, showing multiple misfires across different cylinders. The main culprit was carbon buildup on the injectors, which prevented proper fuel atomization. This is actually a common issue with direct injection engines. This was a serious repair requiring specialized equipment. The job involved removing and testing all injectors, plus cleaning the intake manifold. The ignition coils were also tested during diagnosis since they can cause similar symptoms, but in my case, the injectors were definitely the problem. If your S3 is showing these symptoms, especially with the check engine light, you should get it checked soon. Running the engine with faulty injectors can lead to catalytic converter damage and increased fuel consumption. A proper diagnosis will show if its the injectors or possibly other components like the fuel pump or ignition system.

Thanks for sharing your experience with the fuel injector issue. These symptoms can definitely be tricky to diagnose. The combustion misfire problem with the 2.0T engines often comes down to either the injectors or spark plugs, and in my case, replacing the injectors fixed it completely. Just wondering, do you remember the repair cost for the injector replacement? And has everything been running smoothly since the fix? Would help to know if any other issues popped up afterward that might be related to the original problem. Dealing with similar issues on my S3 now, and trying to get an idea of what to expect cost-wise before heading to the shop.

Good news, I actually just got this fixed last week. The repair shop confirmed the cylinder misfire diagnosis and traced it to a faulty fuel injector. Total bill came to 515 Euro for the complete injector replacement work. Since the repair, the engine runs perfectly smooth with no more rough idle or jerking during acceleration. The combustion misfires detected by the diagnostic scan are completely gone. Its like having a different car, smooth power delivery and no more check engine light. No other related issues have shown up after the fix. If your symptoms match what I described, its worth getting the fuel injectors checked. While spark plugs and ignition coils can cause similar problems, a proper diagnostic scan should pinpoint the exact cause. The investment was worth it to restore proper engine performance and prevent potential damage to other components. Just make sure to get a proper diagnosis first since these symptoms can have multiple causes.

Had the car checked today and wanted to share my experience. The mechanic ran diagnostics and found multiple misfires, exactly matching what others described. The throttle response issues were caused by two bad fuel injectors. Total repair came to 490 Euro including parts and labor. They also inspected the spark plugs while doing the work, they were still good but I had them replaced anyway as preventive maintenance since they were already in there. The difference in performance is night and day. No more jerking during acceleration, engine runs smooth, and the check engine light is finally off. Throttle response is crisp again, especially at lower speeds where it used to stumble. Really glad I got this sorted before it could cause more problems. The mechanic mentioned running too long with faulty injectors risks damaging the catalytic converter. Good thing I asked here first, helped me go in knowing what to expect and probably saved some money by avoiding unnecessary diagnostic time.