A2 Idle Control Issues: Faulty IAC Valve Guide

Had the exact same symptoms on my A3 1.4 from 2000. As someone with basic car maintenance experience, I first thought it was just a simple throttle body cleaning job, but it turned out to be more complex. The stalling engine at idle speed was really annoying, especially at traffic lights. After scanning, my mechanic found the IAC valve and surrounding intake system were heavily contaminated. The air valve wasnt functioning properly because of carbon buildup. The complete cleaning of the intake system, including the throttle body and IAC valve, cost me 425 Euro. Since the repair, the idle speed has been perfectly stable and the check engine light never came back on. Before suggesting specific fixes, could you share: Current mileage on your car, When was the last time you had the throttle body cleaned, Does the stalling happen only when the engine is cold or also when warm, Any other symptoms besides the stalling engine This information would help determine if your issue matches what I experienced with my car.

Had the exact same symptoms on my A3 1.4 from 2000. As someone with basic car maintenance experience, I first thought it was just a simple throttle body cleaning job, but it turned out to be more complex. The stalling engine at idle speed was really annoying, especially at traffic lights. After scanning, my mechanic found the IAC valve and surrounding intake system were heavily contaminated. The air valve wasnt functioning properly because of carbon buildup. The complete cleaning of the intake system, including the throttle body and IAC valve, cost me 425 Euro. Since the repair, the idle speed has been perfectly stable and the check engine light never came back on. Before suggesting specific fixes, could you share: Current mileage on your car, When was the last time you had the throttle body cleaned, Does the stalling happen only when the engine is cold or also when warm, Any other symptoms besides the stalling engine This information would help determine if your issue matches what I experienced with my car.

Had the exact same symptoms on my A3 1.4 from 2000. As someone with basic car maintenance experience, I first thought it was just a simple throttle body cleaning job, but it turned out to be more complex. The stalling engine at idle speed was really annoying, especially at traffic lights. After scanning, my mechanic found the IAC valve and surrounding intake system were heavily contaminated. The air valve wasnt functioning properly because of carbon buildup. The complete cleaning of the intake system, including the throttle body and IAC valve, cost me 425 Euro. Since the repair, the idle speed has been perfectly stable and the check engine light never came back on. Before suggesting specific fixes, could you share: Current mileage on your car, When was the last time you had the throttle body cleaned, Does the stalling happen only when the engine is cold or also when warm, Any other symptoms besides the stalling engine This information would help determine if your issue matches what I experienced with my car.

Thanks for sharing your experience. My current mileage is 140465 KM and the last service was just routine maintenance 3 months ago. No throttle body cleaning was done then. The engine stalling happens both when cold and warm, but its definitely worse during cold starts. The car idle becomes really unstable and occasionally drops below normal. The check engine light has been steady since this started. Your repair cost reference is helpful. If cleaning the IAC valve and throttle body can fix the unstable idle issue, that would be far better than a full replacement. Wondering if I should first try cleaning before jumping to replacement parts.

Thanks for sharing your experience. My current mileage is 140465 KM and the last service was just routine maintenance 3 months ago. No throttle body cleaning was done then. The engine stalling happens both when cold and warm, but its definitely worse during cold starts. The car idle becomes really unstable and occasionally drops below normal. The check engine light has been steady since this started. Your repair cost reference is helpful. If cleaning the IAC valve and throttle body can fix the unstable idle issue, that would be far better than a full replacement. Wondering if I should first try cleaning before jumping to replacement parts.

Thanks for sharing your experience. My current mileage is 140465 KM and the last service was just routine maintenance 3 months ago. No throttle body cleaning was done then. The engine stalling happens both when cold and warm, but its definitely worse during cold starts. The car idle becomes really unstable and occasionally drops below normal. The check engine light has been steady since this started. Your repair cost reference is helpful. If cleaning the IAC valve and throttle body can fix the unstable idle issue, that would be far better than a full replacement. Wondering if I should first try cleaning before jumping to replacement parts.

Really appreciate the additional details about your car. From what you describe, especially the idle issues during both cold and warm conditions, it sounds even more similar to what I experienced. The unstable idle speed in my A3 also showed these exact symptoms before I had the work done. The fact your car struggles more during cold starts is another typical sign of a dirty air valve or throttle body system. Since your last service was recent but didnt include throttle body cleaning, starting with a thorough cleaning makes perfect sense. In my case, the carbon deposits were so severe they were restricting proper air flow through the idle air control valve. A professional cleaning resolved my engine idle issues completely. The repair cost I mentioned (425 Euro) included a full diagnostic check and cleaning of the entire intake system. If you decide to try cleaning first, make sure they do the complete job including both the throttle body and IAC valve, as partial cleaning often doesnt fully resolve the idle problems. Based on the similarities between our cases, I think theres a good chance cleaning will fix your unstable idle without needing to replace parts. Just ensure whoever does the work has experience with these specific idle control systems.

Really appreciate the additional details about your car. From what you describe, especially the idle issues during both cold and warm conditions, it sounds even more similar to what I experienced. The unstable idle speed in my A3 also showed these exact symptoms before I had the work done. The fact your car struggles more during cold starts is another typical sign of a dirty air valve or throttle body system. Since your last service was recent but didnt include throttle body cleaning, starting with a thorough cleaning makes perfect sense. In my case, the carbon deposits were so severe they were restricting proper air flow through the idle air control valve. A professional cleaning resolved my engine idle issues completely. The repair cost I mentioned (425 Euro) included a full diagnostic check and cleaning of the entire intake system. If you decide to try cleaning first, make sure they do the complete job including both the throttle body and IAC valve, as partial cleaning often doesnt fully resolve the idle problems. Based on the similarities between our cases, I think theres a good chance cleaning will fix your unstable idle without needing to replace parts. Just ensure whoever does the work has experience with these specific idle control systems.

Really appreciate the additional details about your car. From what you describe, especially the idle issues during both cold and warm conditions, it sounds even more similar to what I experienced. The unstable idle speed in my A3 also showed these exact symptoms before I had the work done. The fact your car struggles more during cold starts is another typical sign of a dirty air valve or throttle body system. Since your last service was recent but didnt include throttle body cleaning, starting with a thorough cleaning makes perfect sense. In my case, the carbon deposits were so severe they were restricting proper air flow through the idle air control valve. A professional cleaning resolved my engine idle issues completely. The repair cost I mentioned (425 Euro) included a full diagnostic check and cleaning of the entire intake system. If you decide to try cleaning first, make sure they do the complete job including both the throttle body and IAC valve, as partial cleaning often doesnt fully resolve the idle problems. Based on the similarities between our cases, I think theres a good chance cleaning will fix your unstable idle without needing to replace parts. Just ensure whoever does the work has experience with these specific idle control systems.

Thanks for all the insights. I really needed this information to make an informed decision about my car's idle problems. After comparing my symptoms with your experience, I think I'll start with a professional cleaning of both the IAC valve and throttle body. The similarities in how the engine stalling occurs, especially during cold starts, are too close to ignore. Going for a thorough cleaning first makes more financial sense than jumping straight to replacing the idle air control valve. The 425 Euro cost reference gives me a good baseline for what to expect. My unstable idle issues sound nearly identical to what you dealt with, so Im hopeful this approach will work. Will schedule the cleaning service this week and make sure they check the entire intake system while theyre at it. The engine stalling at traffic lights is getting really frustrating, so the sooner this gets fixed, the better.

Thanks for all the insights. I really needed this information to make an informed decision about my car's idle problems. After comparing my symptoms with your experience, I think I'll start with a professional cleaning of both the IAC valve and throttle body. The similarities in how the engine stalling occurs, especially during cold starts, are too close to ignore. Going for a thorough cleaning first makes more financial sense than jumping straight to replacing the idle air control valve. The 425 Euro cost reference gives me a good baseline for what to expect. My unstable idle issues sound nearly identical to what you dealt with, so Im hopeful this approach will work. Will schedule the cleaning service this week and make sure they check the entire intake system while theyre at it. The engine stalling at traffic lights is getting really frustrating, so the sooner this gets fixed, the better.

Thanks for all the insights. I really needed this information to make an informed decision about my car's idle problems. After comparing my symptoms with your experience, I think I'll start with a professional cleaning of both the IAC valve and throttle body. The similarities in how the engine stalling occurs, especially during cold starts, are too close to ignore. Going for a thorough cleaning first makes more financial sense than jumping straight to replacing the idle air control valve. The 425 Euro cost reference gives me a good baseline for what to expect. My unstable idle issues sound nearly identical to what you dealt with, so Im hopeful this approach will work. Will schedule the cleaning service this week and make sure they check the entire intake system while theyre at it. The engine stalling at traffic lights is getting really frustrating, so the sooner this gets fixed, the better.