Audi Q8 Cold Start Fix: Bad Injector vs Other Causes

When my 2018 Audi Q5 2.0 TFSI showed similar symptoms, it turned out to be clogged injectors causing engine misfire and hard starting issues. The initial diagnosis revealed carbon buildup affecting the injector spray pattern. Before replacing parts, we first tried professional injector cleaning and ran injector test procedures. This showed three injectors were not atomizing fuel properly during cold starts, causing the rough running. The fuel system needed a complete service including replacing two faulty injectors. The repair was serious since bad injectors can lead to: Increased fuel consumption, Engine damage if left untreated, Failed emissions tests, Further carbon buildup Getting proper injector diagnosis with specialized equipment is crucial before replacing parts. The cold start issues usually worsen over time if not addressed. In fuel system repairs, using OEM parts is important for reliable operation. A full injector replacement was ultimately needed in my case, as cleaning alone did not resolve the spray pattern issues. The symptoms disappeared completely after repair and cold starts have been perfect since. The quote you received is in line with what this type of work typically costs, considering the parts and labor involved for your Q8 model.

Thanks for sharing your Q5 experience. My symptoms sound identical, rough idle and difficult starts in the morning. I went ahead with the injector replacement last month since I was worried about potential engine damage from poor fuel delivery. Quick question, do you remember roughly what you paid for the full repair? Mine came to 780 Euro including parts and labor. Also curious if youve had any other fuel system issues pop up since getting it fixed? My cold starts are much better now but I notice occasional hesitation that makes me wonder if the fuel rail needs attention too.

Thanks for asking about the repair costs. My full injector service ended up being 515 Euro, which included replacing the faulty cold start injector and testing the fuel delivery system. The price difference likely comes down to labor rates and specific parts needed for different models. Since fixing the defective injection valve, my cold starts have been flawless with no fuel system issues whatsoever. The rough idle completely disappeared and the engine runs smoothly from startup. The hesitation you mentioned could indeed be related to fuel rail pressure, might be worth having that checked if it persists. The investment in fixing the cold start injector was definitely worth it, as poor fuel delivery can lead to more expensive problems if left unchecked. A properly functioning fuel system is crucial for engine longevity and performance. If youre still experiencing hesitation, having the fuel rail pressure tested would be a logical next step to ensure optimal fuel delivery across all operating conditions.

Appreciate the detailed responses everyone. Just wanted to close the loop on my cold start problems. Finally got the repair done last week, ended up paying 780 Euro for the injector replacement plus diagnostic work. The mechanic showed me the old injector which was pretty badly gunked up, definitely affecting the fuel delivery. Happy to report the engine fires up perfectly now even on cold mornings. No more rough idle or hard starts. The slight hesitation I mentioned earlier also cleared up on its own after a few tanks of premium fuel, so looks like the fuel rail is working fine. The service included a full computer scan and fuel system pressure test to make sure there weren't any other issues hiding. While not cheap, seeing the difference in how the engine runs now makes me glad I didn't put off fixing it. Much better to address injection system problems early before they cause more expensive damage. Think this can be marked as solved. Thanks again for helping confirm I was on the right track with the repair.