S5 Injector Issues Causing Multiple Performance Problems

Had similar issues with my 2018 RS4 with the 2.9L gasoline engine. The symptoms matched exactly, rough idle, engine misfire, high fuel consumption, and power loss during acceleration. The diagnosis confirmed dirty fuel injectors. In my case, this was a serious issue because prolonged operation had created carbon buildup inside the injection valves. The technician showed the contamination was blocking proper fuel atomization. The repair required complete removal and ultrasonic cleaning of all injectors. They also performed fuel system cleaning and replaced the fuel filter since debris in the system likely caused the initial contamination. To ensure quality work, request: Pre and post repair diagnostic readings, Inspection of removed parts, Full system pressure testing after replacement, Test drive confirmation This isnt a quick fix, proper injector service requires specific equipment and expertise. The engine needs careful timing adjustment after installation. Most shops need at least a full day for this job. Without proper repair, continued operation risks additional engine damage from poor fuel distribution and incomplete combustion.

Thanks for the detailed response about injector issues. Your experience sounds identical to what I went through with my S5. The symptoms caused a lot of anxiety since the vehicle was relatively new. Good call on the comprehensive repair approach, my first attempt with just a fuel system cleaner did nothing to help. I am curious about the final costs for your repair. The shop gave me quite a range when I called around. Also, has everything stayed running smoothly since the fix? My repair was recent and I want to know if I should watch for any recurring symptoms. The emissions and performance have been much better since fixing the clogging, but I keep a close eye on fuel consumption just in case the problem returns.

Good to hear you got the issue sorted. After my repair experience with the injector replacement, I can confirm everything has been running perfectly for over 8 months now. The engine performance returned to normal immediately after the fix, and fuel consumption stabilized at factory specs. The total repair cost was 515 Euro which included cleaning the defective injection nozzle, labor, and a new fuel filter. While it might seem steep, the improvement in engine performance and efficiency made it worthwhile. The misfire issues completely disappeared after the repair. A tip for prevention: I now use premium fuel exclusively and changed to shorter service intervals. This helps avoid future injection valve contamination. The engine runs remarkably smooth at idle now, unlike before when it would constantly struggle. No recurring symptoms have appeared since the fix. If you maintain regular service schedules and use quality fuel, you shouldnt face this problem again. The initial repair cost is definitely better than risking more extensive engine damage down the line.

Finally went to get my S5 checked out after dealing with those frustrating injector problems. The mechanic confirmed exactly what was mentioned, clogged injectors causing all those performance issues. Really glad I didnt wait longer as the diesel-like black smoke coming from the exhaust was apparently a sign of serious fuel delivery problems. The repair took a full day as they had to remove, clean, and test each injector. Ended up costing 680 Euro total including parts and labor. They showed me the gunked-up injectors, pretty shocking how much buildup there was for a relatively new car. Noticed immediate improvements after the fix. The engine idles perfectly now, emissions are clean, and that annoying power loss during acceleration is completely gone. Fuel economy is back to normal too. For anyone facing similar symptoms, dont waste time with quick fixes. Get it properly diagnosed and repaired before the clogging causes more expensive engine damage. Planning to stick with premium fuel and regular maintenance from now on to prevent this from happening again.