RS4 Misfire: Rough Running & Acceleration Troubles

Recently dealt with similar symptoms on my A4 2.0T (2012). The rough idle and jerking during acceleration initially seemed like ignition coil issues, but diagnostic testing revealed multiple problems. The primary culprit was failing fuel injectors causing uneven fuel delivery. Secondary issues included a clogged air filter and carbon buildup on intake valves. These combined problems created inconsistent combustion, triggering the check engine light. While checking the engine, the mechanic also found an exhaust leak at the manifold gasket. This was a serious issue requiring immediate attention, as exhaust leaks can affect engine performance and pose safety risks. The repair involved replacing the gasket and resurfacing the manifold flange to ensure proper sealing. Key diagnostic steps should include: Testing fuel injector performance, Checking ignition coil resistance, Inspecting the fuel pump pressure, Examining exhaust system integrity, Scanning for specific error codes When visiting a shop, request these specific diagnostic tests. A thorough inspection will help avoid misdiagnosis and ensure all related issues are identified.

Thanks for sharing your experience with the A4. Dealing with similar issues on my RS4 right now. Along with replacing the ignition coils and spark plugs, the shop found the crankshaft sensor was also faulty, which was contributing to the erratic performance. Did you track how much the total repair cost? Also curious if youve had any recurring issues since the work was done? Always good to know what to watch out for with these engines.

Since having the repairs done on my A4, the uneven engine running issues have completely disappeared. The exhaust leak repair cost 265 Euro, which included the new gasket and manifold resurfacing. The previous fuel injector and air filter work was done separately. The engine now runs smoothly with no check engine light warnings. Following the repairs, I had no recurring problems with the fuel delivery system or ignition components. The crankshaft sensor replacement you mentioned is a smart fix, these sensors can definitely cause similar symptoms when they start failing. One tip: keep monitoring for any exhaust leaks during routine maintenance. Even small leaks can affect engine performance and trigger those frustrating misfires we both experienced.

I finally got the RS4 back from the shop last week. The total repair bill came to 890 Euro, covering new ignition coils, spark plugs, and the crankshaft sensor replacement. The oxygen sensor also needed cleaning, which they did while the other work was being done. The diagnostic process was thorough, they ran complete computer scans and pressure tests before starting any repairs. This approach helped identify all the issues at once, avoiding multiple visits. The timing belt was also inspected and thankfully showed no wear issues. After a week of driving, the engine runs perfectly with no rough idle or jerking during acceleration. No check engine light since the repairs. The shop explained that the faulty crankshaft sensor was causing incorrect timing signals, leading to the engine misfire symptoms I experienced. The extra cost was worth it for proper diagnosis and repair. Much better than my previous experience where the other shop just kept replacing unusual parts without fixing the core issue.