IAC Valve Stalling: Fix it Right or Check Twice?

Had the same issue on my '07 Canyon with the 3.7L. The IAC valve was causing erratic idle speed, but turned out the bigger problem was severe carbon buildup in the throttle body. When I took it in, they found the intake was heavily contaminated, restricting proper airflow. The fix required cleaning the throttle body and replacing the IAC valve since it was damaged from working overtime to compensate for the restricted airflow. This is actually a serious issue since it can lead to complete stalling and potential engine damage if left unchecked. The flashing check engine light typically indicates a misfire, which matches these symptoms. Quick test you can try: If the idle smooths out temporarily when you give it a slight gas tap, it's likely throttle body/IAC related. Don't wait too long on this repair, dirty throttle bodies often end up killing IAC valves. Would definitely recommend getting both the throttle body cleaning and IAC valve replacement done together if that's the verdict. These systems work in tandem to control idle speed.

Had the exact same symptoms with my Colorado a while back. Engine stalling kept getting worse, especially when idling at stops. Started with occasional rough idles but progressed to full stalls. The air intake system was completely gunked up, and like yours, the check engine light was going crazy. Got the IAC valve replaced and had them do a thorough throttle body cleaning while they were at it. Made a massive difference, idle control is smooth as silk now, no more stalling engine issues. Wanted to check how much the repair ended up costing you and if you've had any other issues pop up since getting it fixed? Always good to know what to watch out for with these engine stalling problems.

Just had the work done last week, the mechanic confirmed it was definitely the bad idle air control valve causing the stalling issues. Total bill came to 425€ for the complete job. They found heavy contamination in the air intake system, just like I suspected. Since getting it fixed, the engine idle is perfectly stable, no more stalling or rough running. They did a deep clean of the entire intake system along with replacing the IAC valve, which was absolutely necessary given how gunked up everything was. Worth every penny considering how smoothly it's running now. Haven't seen a single engine stalling incident since the repair, and the idle control is working exactly as it should. The check engine light hasn't come back either. Pro tip: Regular throttle body cleaning can prevent these issues from developing in the first place. Might be worth adding it to your maintenance schedule every 30k miles or so to avoid future air intake problems.

Thanks everyone for the advice, wanted to give a quick update on how it all turned out. Finally took it to my mechanic last week for the IAC valve issue. Was getting really tired of the constant stalling at lights! The diagnosis was spot-on. My throttle body was completely clogged up and the idle air control valve was shot. Ended up paying €385 for the full service, new IAC valve installation plus a deep clean of the throttle body and intake system. The difference is like night and day. Engine idles perfectly now, no more unusual stalling or rough running. Engine holds a steady idle speed whether I'm in park or at a stoplight. Best part is the check engine light has stayed off since the repair. Mechanic showed me all the gunk they cleaned out, pretty shocking how bad it was. Definitely learned my lesson about regular maintenance. Going to make throttle body cleaning a regular thing from now on to protect the idle control system. Worth every penny to finally have it fixed right. No more anxiety about whether the engine's going to die at every stoplight!