RS5 Throttle Whistling Points to Air System Failure

As an RS7 owner who faced similar issues last year at 165000 KM, that whistling sound combined with rough running strongly suggests a vacuum leak in your air intake system. The symptoms match what I experienced, engine stalling at idle and inconsistent throttle response. A thorough inspection revealed the problem was a deteriorated vacuum hose connecting to the throttle body. These hoses become brittle over time, creating small cracks that disrupt proper air supply to the engine. The mechanic found multiple connection points where the vacuum lines had developed hairline cracks, allowing unmetered air to enter the system. This explained the check engine light and rough running conditions. The repair required replacing several vacuum lines and testing the entire air intake system for proper seal. The throttle body itself needed cleaning as well, since unfiltered air had been entering through these leaks. This is considered a serious issue as it affects engine performance and fuel economy, potentially leading to more severe problems if left unaddressed. A proper fix requires pressure testing the entire vacuum system to locate all potential leaks, not just resetting the warning light. The whistling noise you describe is a classic symptom of a vacuum leak disrupting the air supply.

Thanks for sharing your RS7 experience. That sounds exactly like what I am dealing with on my RS5. The vacuum leak diagnosis makes sense given the symptoms. Did you keep track of the total repair cost for the vacuum hoses and throttle body service? Also curious if youve had any related issues pop up since getting it fixed. My mechanic quoted a pretty high price so trying to get a sense if its in line with what others paid. The engine stalling and whistling noise is getting worse so definitely need to address it soon. Just want to make sure I am getting the right fix at a fair price.

Had the work done last week and yes, it solved all those issues completely. The manifold pressure is now stable and the engine runs smooth without any whistling sounds. Total cost was 175 Euro for replacing the faulty hose connection between the pump and air valve. Since fixing the vacuum hoses, the idle problems disappeared completely and the check engine light hasnt returned. The throttle body response is much better now, and fuel economy has improved too. No more stalling or rough running. Worth noting that a proper diagnosis with pressure testing was key, just like your mechanic suggests. The price youre being quoted might seem high, but considering the specialized testing equipment needed and labor involved in accessing all those connections, its actually reasonable for this type of repair. If the symptoms are getting worse, dont wait too long. Small vacuum leaks can develop into bigger issues affecting other engine components over time.

I finally went ahead with the repair yesterday after dealing with those annoying idle problems for weeks. The mechanic found exactly what we suspected, cracked vacuum lines near the throttle body causing air intake issues. The whole system needed pressure testing to find all the leaks. Total cost came to 850 Euro which included replacing three damaged vacuum hoses, cleaning the throttle body, and full diagnostic testing. More than I wanted to spend but the engine runs perfectly now. No more check engine light, weird whistling noises or engine stalling issues. The mechanic showed me the old hoses and you could clearly see the cracks letting unmetered air into the system. Good call on getting it fixed before it caused more problems. The car feels like new again with proper air supply restored. Really appreciate the advice that helped identify the issue correctly.