Atlas rough idle and CEL linked to vacuum system issues

The symptoms you describe match what happened with my 2017 VW Tiguan. The engine stalling and rough idle problems turned out to be a combination of issues with the throttle body and a vacuum leak near the air intake system. The mechanic found that the rubber hose connecting the pump to the air valve had deteriorated, causing inconsistent airflow. This created erratic idle speeds and triggered the check engine light. The repair required replacing the damaged hose and cleaning the throttle body assembly. This was a serious issue that needed immediate attention since the improper air-fuel mixture could have led to more severe engine damage if left unaddressed. The symptoms worsened gradually over time, starting with minor idle problems and eventually affecting overall engine performance. When visiting the mechanic, request they specifically check: Vacuum lines for cracks or loose connections, Throttle body for carbon buildup, Air intake system for leaks, PCV valve operation, Mass airflow sensor readings These components often work together, so having them all inspected makes sense given the symptoms.

Thanks for sharing your experience with the Tiguan. That sounds exactly like what I am dealing with, especially the rough idle and manifold pressure issues. I will definitely have them check all those components you listed. Would you mind sharing how much the repair ended up costing? Also curious if you have had any similar problems since getting it fixed? I want to make sure I budget appropriately and wondering if this might be a recurring issue with the throttle body or air intake system.

Had the repair done last week and everything is running perfectly now. The manifold pressure stabilized immediately after they fixed the faulty hose connection between the pump and air valve. Total cost was 175€ for parts and labor, which seemed reasonable given the diagnostic work needed to pinpoint the exact issue. The idle problems completely disappeared and engine stalling is no longer a concern. No recurring issues with the throttle body or air intake system since the repair. The mechanic mentioned these hose connections typically last the lifetime of the vehicle, so this was likely a one-time fix unless there was unusual wear and tear. The key was catching it early before the inconsistent airflow could cause more extensive engine damage. Worth noting that a proper diagnosis made all the difference, having them check the entire air intake system revealed the exact problem instead of just replacing parts out of nowhere.

I followed up and took my Atlas to the mechanic last week. The vacuum leak diagnosis was spot on. They found a cracked vacuum hose near the intake manifold that was causing the air supply issues. The check engine light cleared up right after they replaced the faulty hose and did a thorough inspection of the surrounding components. Total repair came to 220€, which included replacing the vacuum hoses and cleaning the throttle body. The manifold pressure is now stable and the rough idle completely disappeared. No more rpm fluctuations either. The mechanic mentioned these issues are fairly common after 100000km and recommended keeping an eye on the rubber components around the intake system. Really glad I caught this early before it led to bigger engine problems. The car runs like new again and no warning lights have come back on. Thanks for helping point me in the right direction with this repair.