RS7 Cold Start Issues Point to Faulty Fuel Injectors

Had the exact same symptoms on my 2019 RS6. Started with rough idle and cold start issues, which made me suspect fuel delivery problems right away. With some experience working on performance cars, I knew this needed professional diagnosis. The workshop ran a complete fuel injector test and found one defective injector causing uneven fuel delivery. They also checked the entire fuel rail system to ensure proper pressure. Cleaning alone wasnt enough, one injector needed replacement. Total repair came to 515 Euro including: Full diagnostic scan, Fuel injector removal and testing, New injector installation, System pressure verification, Test drive to confirm fix Since the repair, cold starts are perfect and the rough idle is completely gone. The fuel delivery is now consistent at all temperatures. Before suggesting more specific advice, could you share: Current mileage? Any check engine lights? Have you noticed any fuel consumption changes? When was your last fuel system service? This information would help determine if your symptoms match what I experienced or point to a different fuel system issue.

My RS7 has 158210 KM and just had its annual service last month. The check engine light has been flickering intermittently, and fuel consumption increased by about 15% in the past weeks. This engine misfire during cold starts is seriously concerning, especially since the hard starting issues began appearing right after a full tank fill-up. The rough idle symptoms match exactly what you described, it takes several attempts to start, runs poorly for 3-4 minutes, then smooths out once warmed up. Could definitely be fuel delivery problems like in your case. The service records show no previous fuel system maintenance besides regular filter changes. Your detailed repair breakdown helps, will have the shop focus on testing injectors and fuel rail pressure first.

Thanks for sharing those details, the symptoms line up exactly with what I experienced. The combination of increased fuel consumption, check engine light, and cold start problems points strongly toward fuel delivery issues, just like my RS6 case. The timing after your fuel fill is interesting. While my injector problem developed gradually, your sudden onset could indicate contaminated fuel aggravating an existing weak injector. The cold start injector is particularly sensitive to fuel quality issues. In my repair, the workshop found the fuel rail pressure was inconsistent during cold starts, causing the rough idle. The faulty injector was making the fuel delivery even more erratic. Your 158210 KM is close to when I had my issues at 162000 KM. Quick tips from my experience: Request a fuel pressure test at cold start, Have them check injector spray patterns, Consider a fuel system cleaning before replacing parts, Use high quality fuel for a few tanks My repair solved the problem completely, but catching it early saved my other injectors from excess wear. Given your identical symptoms and similar mileage, having the fuel system professionally diagnosed now could prevent more extensive repairs later.

Based on your insight and repair experience, I will schedule a diagnostic appointment this week. Your fuel delivery problems match my symptoms perfectly, especially the correlation between mileage and failure patterns. The engine misfire during cold starts has become more frequent, and I cannot risk damaging other components by delaying repairs. Your repair cost breakdown gives me a good reference point for what to expect. I will request the specific tests you mentioned: Full injector diagnosis including spray patterns, Fuel rail pressure testing, Complete system inspection I already switched to premium fuel after the issues started, but knowing that contaminated fuel might have triggered these cold start problems, I will stick to reputable stations going forward. Will update once the shop completes their diagnosis. The fact that your repair fully resolved similar issues gives me confidence this can be fixed without major complications. Hopefully just needs injector service or replacement like in your case.