Audi A4 Misfire: Key Culprits Behind Rough Performance

Having experienced similar symptoms on my A6 2004 gasoline model, I can relate to this issue. The rough idle and power loss turned out to be failing fuel injectors, which was causing engine misfiring across multiple cylinders. The initial symptoms matched yours exactly, inconsistent throttle response, significant power loss, and that distinctive rough idle, especially when the engine was cold. The check engine light would come on during acceleration, which is a classic sign of combustion issues. In my case, the diagnosis revealed two faulty injectors that were not atomizing fuel properly. This created an inconsistent air-fuel mixture, leading to incomplete combustion. The repair involved replacing all fuel injectors as a set, which is generally recommended to ensure balanced fuel delivery. This was indeed a serious issue that required immediate attention, as running the engine with faulty injectors can lead to catalyst damage and increased fuel consumption. The problem also affected the ignition coils and spark plugs, which showed premature wear due to the poor combustion conditions. A proper fix typically involves: Testing fuel pressure and injector spray patterns, Checking for carbon buildup in the intake, Replacing faulty injectors, Installing new spark plugs, Verifying ignition coil condition The repair resolved all symptoms and restored proper engine performance.

Thanks for sharing your experience with the fuel injectors. That cylinder misfire issue sounds exactly like what I dealt with last month. My rough idle turned out to be caused by failed ignition coils, and the check engine light was constantly flashing. Do you remember the total cost for your repair work? Also curious if youve had any similar issues pop up since getting it fixed.

Just had my A6 checked by the mechanic last week actually. The combustion misfires detected earlier were completely fixed after replacing one faulty injection valve. Total repair cost came to 515 Euro for parts and labor, which included cleaning the fuel system. The rough idle and engine misfiring issues have not returned since the repair. The car runs smoothly now with no check engine light or power loss problems. When these cylinder misfire symptoms first appeared, I was worried it might be something more serious with the fuel pump, but the injector replacement solved everything. Worth mentioning that proper diagnosis was key here, a faulty injector can sometimes mimic spark plug or ignition coil problems, which is why professional testing is important to pinpoint the exact cause of misfiring.

After getting your feedback, I finally took my car to a new mechanic last week. The throttle response issues were driving me crazy, so I had to get it sorted. Turns out two ignition coils were completely shot and causing the combustion misfire problems. The rough idle was exactly as you described. The repair bill came to 380 Euro including new spark plugs, since they recommended replacing those while they were at it. Much better than I expected after that previous bad experience with my old mechanic. Car runs great now, no more jerking during acceleration and the check engine light has stayed off. Such a relief to have it running properly again. Really appreciate the help in figuring out what was going on.