VW Suran Stalling: Idle Air Control Valve Issues Fix

Having worked on cars as a hobby mechanic for several years, I dealt with a very similar idle control issue on my VW Fox 2012. The symptoms were exactly as you describe, unstable engine idle and stalling at stops. After taking it to my regular workshop, they found the throttle body and intake system were heavily contaminated, causing irregular air flow. The idle air control valve was barely functioning due to carbon buildup. The complete cleaning service and diagnostic check cost me 425€, but it completely resolved the unstable idle. The throttle body cleaning made a huge difference, the engine now maintains steady idle and no more stalling. Regular maintenance of the air intake system is crucial to prevent these issues. Could you share some additional details to help diagnose this better: Current mileage on your Suran, When was the last throttle body cleaning done, Are there any other symptoms besides the unstable idle, What specific error codes is it throwing This information would help determine if your issue matches what I experienced and whether a thorough intake cleaning might solve it.

Last service was done at 122000km but only oil change and filters. The idle air control valve has never been changed in my car. I did bring it to a shop recently and they got error code P0505 indicating an IAC valve malfunction. The stalling engine issue started about 2 weeks ago and gets worse in cold weather. The check engine light comes on intermittently, usually when the car idle gets really rough. Besides the unstable idle and stalling, I also notice the RPMs fluctuate a lot between 500-1000 even when just sitting at a light. Based on what you shared about the cleaning service, I might try that first before replacing parts.

Thanks for those additional details. Your symptoms and error code match exactly what I experienced with my Fox before getting it fixed. The P0505 code specifically points to the idle control valve, but in my case, a full cleaning resolved it without needing replacement parts. The RPM fluctuation between 500-1000 is a classic sign of a contaminated throttle body and idle air control system. When the carbon buildup gets bad enough, the idle speed control becomes erratic, especially in cold weather when the engine needs more precise air management. Since your car has never had the idle air control valve serviced, starting with a professional cleaning is definitely the smart approach. My mechanic first tried cleaning the throttle body and idle control components before suggesting any parts replacement. The improvement was immediate, stable idle speed, no more stalling engine, and the check engine light stopped appearing. If the cleaning doesnt fully resolve the issue, then you might need to consider replacing the idle air control valve. But based on my experience with the same symptoms, I would be surprised if a thorough cleaning doesnt fix it. The total diagnostic and cleaning service should cost significantly less than replacing parts. Just make sure whoever does the work uses proper throttle body cleaner and follows the correct cleaning procedure for our VW engines.

Thanks for the input. After hearing about your similar experiences, I will definitely start with getting the idle control system professionally cleaned before jumping to replacing the air valve. The matching error code P0505 and similar symptoms, especially the RPM fluctuations and cold weather sensitivity, make me pretty confident this is the right approach. Going to schedule the throttle body and air intake cleaning service next week. The cost seems reasonable compared to full parts replacement, and it makes sense to try this first given my car has never had this service done in 122000km. Will update the thread once I get the work done to let everyone know if it resolved my engine idle and stalling issues. Really appreciate all the detailed advice and sharing your repair experiences. This saved me from potentially spending money on unnecessary parts replacement before trying the cleaning service.