Audi S6 Air Flow Issues Point to Throttle System Fix

Had a similar issue with my Audi S4 (2015). The symptoms matched exactly, engine struggling with air supply and recurring check engine warnings. A comprehensive inspection revealed multiple vacuum leaks where the hoses connected to the intake manifold pressure system. The main culprit was deteriorated vacuum hoses that developed tiny cracks, causing inconsistent manifold pressure readings. The engine stalling symptoms became more noticeable during idle and acceleration. The throttle body was initially suspected, but after testing, it turned out to be entirely related to the vacuum system. The fix required replacing several vacuum hoses and resealing connections at multiple points. This was classified as a serious issue since failing to address it could lead to further engine performance problems and potential damage to other components. The repair proved to be a permanent solution, no check engine lights or performance issues since then. Worth noting that vacuum leaks often get misdiagnosed as throttle body problems, so insist on having the entire vacuum system thoroughly tested before agreeing to any repairs.

Thanks for sharing that experience with the vacuum leaks. Same symptoms plagued my S6 last winter, engine stalling, erratic idle, and constant check engine warnings. After getting it fixed, I noticed a huge difference in how the engine runs, especially when cold. The air intake system feels much more responsive now. Did you keep track of what the total repair cost? Also wondering if youve had any other air flow related issues pop up since fixing those vacuum leaks? My throttle body occasionally still feels a bit hesitant on startup.

Glad the symptoms match what I experienced, air flow problems can be tricky to diagnose correctly. Since my last reply, I went ahead and had the specific air valve issue fixed, total cost came to 175 Euro for replacing the defective hose connection from the pump to valve. The problematic vacuum leak was causing those idle problems you mentioned. The throttle hesitation you describe on startup could be related to residual air intake issues. In my case, after fixing the main vacuum hoses and connections, the engine has been running smoothly with no engine stalling or vacuum leak symptoms. The idle is stable now, even during cold starts. The repair investment was worth it, no check engine lights or air flow problems in the months since. If your throttle body still feels hesitant, might be worth having the air intake system checked again, focusing specifically on the connection points where vacuum leaks commonly develop.

Thanks for the helpful details. Finally got this sorted last week. Took it to a shop that specializes in German cars. The mechanic found multiple vacuum hoses had developed tiny splits causing those air flow issues. The check engine light kept coming on because the system was detecting irregular pressure readings. The repair involved replacing three vacuum hoses and cleaning the throttle body. Total bill came to 320 Euro for parts and labor. Since the fix, the engine idles perfectly and that annoying hesitation on startup is completely gone. The mechanic showed me the old hoses, they were in pretty rough shape with obvious wear around the connection points. The whole experience taught me not to ignore these symptoms. What started as a minor idle problem could have led to more serious engine issues if left unchecked. Having a mechanic who took the time to properly diagnose the vacuum system rather than just throwing parts at the problem made all the difference.