Q: Car will stall while on a red light or at a stop randomly

Hi there. It sounds like the idle air control valve is sticking when you come to a stop. This valve closes when the throttle is open and reopens to maintain idle when you let off the throttle in the case of coming to a stop. Sometimes cleaning the valve thoroughly with carb cleaner will help this symptom. However, valve replacement is generally the ultimate repair as the valve motor may be damaged from repeated attempts to control the idle speed. If you need help with this, YourMechanic has several technicians, that can assist with diagnosis of the stalling condition.