RS7 Stalling Mystery: Idle Control Valve Suspected

Had nearly identical issues with my 2012 S7. Started with unusual stalling at idle and the check engine light staying on. With some experience working on performance cars, I initially thought it was just the IAC valve acting up. Took it to a workshop after my initial checks of the air intake system didnt reveal anything obvious. Turned out the throttle body and entire intake tract were heavily contaminated, restricting proper airflow. This was causing the erratic idle and stalling engine symptoms. The complete cleaning service cost 425 Euro, including: Professional throttle body cleaning, Air intake system decontamination, Diagnostic scan and reset, IAC valve inspection and cleaning After the service, the idle problems completely disappeared and the engine light cleared. The car now maintains a steady idle without any stalling issues. What have you checked so far? Also, knowing your mileage and maintenance history would help determine if this could be a similar case. Have you noticed any performance changes before the stalling started?

Thanks for your helpful insight. My last service was just 2 months ago at 17930 KM, and they did a routine inspection without flagging any issues. I have checked the air intake components visually but did not do any deep cleaning yet. The engine stalling started quite suddenly last week. Before the idle problems began, the car ran perfectly with no performance issues. Based on your experience, I will get the throttle body and air valve system professionally cleaned first. Given the similarities in our symptoms, this seems like a logical starting point before exploring more complex fixes for the engine idle problems.

The cleaning service definitely solved our similar idle issues, but given your low mileage and recent service, we might want to look at a few other things before spending on a full cleaning. Since your idle problems started suddenly, I would first check the air valve connections and wiring. On my S7, a loose connector at the idle control valve caused similar symptoms once before the actual contamination issue occurred. Our throttle body design can be quite sensitive to even minor irregularities. When my engine stalling issues first appeared, the idle speed would fluctuate out of nowhere until the engine finally cut out. But in my case, this developed gradually over several weeks, unlike your sudden onset. Try this quick check: With the engine at normal operating temperature, listen near the throttle body for any unusual sounds when the idle speed changes. In my experience, a failing idle control valve often makes a slight clicking or buzzing noise. Given the sudden nature of your problem, I would recommend getting the idle control system electronically diagnosed before investing in cleaning services. The diagnostic scan should clearly show if the air valve is actually failing or if the erratic engine idle is caused by something else.

Based on your last message, I will have the idle control system properly diagnosed first. It makes sense to check the electronics before diving into cleaning, especially since my issues appeared so suddenly and the car has low mileage with recent service. I just checked for unusual sounds near the throttle body while the engine was warm, and there is indeed a faint clicking noise when the idle speed changes. This seems to match what you mentioned about potential idle control valve issues. I will schedule a diagnostic scan tomorrow to properly check the air valve and related systems. Once I know whether its an electronic or mechanical issue causing the engine stalling, I can decide if cleaning is needed or if the idle control valve requires replacement. Will update once I have the diagnostic results and know what is actually causing these idle problems.