Audi Q3 Idle Stalling Points to Control Valve Issue

Had a similar issue with my 2021 Audi Q5 last winter. As someone who does basic maintenance but leaves complex issues to professionals, this one had me concerned. The engine idle was extremely unstable, especially during warm-up, and the car would occasionally stall at traffic lights. The throttle body was heavily contaminated, affecting the idle speed control. The engine would run fine once warmed up and at higher RPMs, but the idle problems were really noticeable. Took it to a workshop where they did a thorough cleaning of the intake system and throttle body. Total cost was 425 Euro, including labor and cleaning materials. Since then, the engine idle has been perfectly stable with no more stalling issues. Before suggesting specific solutions, could you share: Current mileage on your Q3? When was the last time you had a major service? Are you using premium fuel as recommended? Does the stalling happen more frequently in any specific weather conditions? These details would help determine if your issue is similar to what I experienced. Engine stalling at idle can have multiple causes, so its important to get an accurate diagnosis.

Just had my service done last week at 149133 KM. The stalling issues started right after. From what I understand now, the IAC valve symptoms do match exactly what Im experiencing. When the service techs cleaned the throttle body and air intake system, they might have dislodged some carbon deposits that are now affecting the idle control. The engine runs perfectly at higher RPMs, but the unstable idle is really concerning, especially during the morning warm-up period. The check engine light stays on consistently, and the air valve seems to be making a slight clicking noise when the engine is idling. Think I should have them inspect the entire intake system again. This type of idle problem usually points to either a clogged air passage or a failing IAC valve based on what Im reading.

Thanks for providing those details about your Q3. The timing of the stalling issues starting right after the service definitely raises some red flags. Your symptoms strongly match my experience with the air intake system problems on my Q5. The clicking noise from the air valve combined with the unstable idle is almost identical to what I dealt with. In my case, when the techs cleaned the throttle body, they didnt properly reset the idle control parameters in the ECU. The dislodged carbon deposits also caused problems with the air intake system. A full inspection of the idle air control valve and intake system makes sense here. When my Q5 had this issue, the workshop found that carbon deposits had actually worked their way into the IAC valve after the initial cleaning. The engine stalling got worse until they did a complete cleaning and proper electronic reset. The stable performance at higher RPMs but problems with engine stalling at idle is a classic sign of idle control issues. You might want to have them check if the throttle body cleaning was done properly and ensure no debris is blocking the air passages. For reference, the complete diagnosis and proper cleaning of my system, including resetting the idle parameters, cost around 380 Euro. Definitely worth it to prevent any long-term damage to the engine.

Thanks for sharing the experience with your Q5. Based on the symptoms and timing after my service, I will definitely get the car back to the workshop. Really concerned about these engine stalling issues, especially since they started right after the service work. The clicking noise from the idle air control valve and unstable idle speed make a lot of sense now. Good to know about the potential issue with dislodged carbon deposits and improper ECU reset after cleaning. Will have them specifically check if any debris is blocking the air intake system. 380 Euro seems reasonable for a proper diagnosis and cleaning. Better to address this now before it causes more problems. Will book it in next week and make sure they do a complete inspection of the IAC valve and reset all idle control parameters properly. The engine stalling during warm-up is getting worse, so cant really delay this fix any longer. Appreciate the detailed explanation about your similar experience, helps confirm my suspicions about what might be causing these idle problems. Will update once I get it sorted out.