Rough Running Scirocco: Bad IAT Sensor Warning Signs

As someone with a 2011 Golf GTI, I can relate to this issue. Having some experience with VW engines, these symptoms definitely align with a faulty IAT sensor. My car showed similar problems, rough idle, power loss, and the dreaded check engine light. The diagnostic tool at my workshop confirmed the intake air temperature sensor was sending incorrect readings to the ECU. This caused the engine to run with wrong air-fuel mixtures, especially during cold starts. The total repair came to 155€, which included: Full diagnostic scan, IAT sensor replacement, Clearing fault codes, Brief test drive to confirm fix After replacing the car sensor, all engine issues cleared up completely. The idle smoothed out, power returned to normal, and the check engine light stayed off. Before suggesting more specific advice, could you share: Current mileage on your Scirocco, Any recent maintenance or repairs, Whether the problem gets worse in particular weather conditions, If you notice any unusual sounds or vibrations This information would help determine if there might be related issues needing attention beyond the air temperature sensor.

Thanks for sharing your GTI experience. Just had my service done at 136712km, and your symptoms match exactly what I experienced with my Scirocco. The car diagnostics confirmed irregular temperature readings from the sensor. I checked my service records and noticed the intake air temperature sensor was never replaced. With these high mileage readings and age, it makes sense the sensor could be failing now. The repair cost you mentioned seems reasonable. Did your workshop perform any additional tests to rule out other potential causes before replacing the temperature sensor? Also wondering if cleaning the air intake system was part of your service, as this might be worth doing while accessing the sensor. The weather aspect you mentioned is interesting, my issues do seem worse during cold morning starts.

Thanks for the follow-up about your Scirocco. On my GTI, the workshop did run a comprehensive diagnostic scan first, focusing specifically on the intake system and related car sensors. The irregular temperature readings were consistent across multiple test cycles, which made the faulty air temperature sensor diagnosis pretty definitive. They did suggest cleaning the intake system, but in my case, it wasnt actually necessary. The mass airflow sensor readings were normal, and there were no carbon deposits affecting the sensor performance. The air filter was also recently changed during regular maintenance. The cold morning correlation you mentioned was identical to what I experienced. The engine issues were most noticeable during the first 5-10 minutes of cold starts, which is a classic sign of temperature sensor problems. The ECU relies heavily on accurate temperature readings for initial fuel mapping. Since your mileage is similar to what mine was when the sensor failed (around 130000km), and considering the age of these VW engines, replacing the intake air temperature sensor should resolve your engine issues completely. Just make sure the workshop uses OEM parts, I learned that aftermarket sensors can sometimes cause intermittent reading problems.

Thanks for the detailed responses. After getting my Scirocco checked, it turns out you were right about the IAT sensor being the problem. The mechanic confirmed irregular temperature readings were causing the engine management issues. The total repair came to 165€, slightly more than your GTI repair because they recommended cleaning the intake system while they were in there. The car diagnostics showed some carbon buildup that could have eventually affected the new temperature sensor readings. The difference in cold start performance is remarkable. No more rough running or power loss, and the check engine light has stayed off. The temperature sensor replacement definitely solved all the issues I was experiencing. For anyone searching the forum later with similar symptoms, having the car sensor professionally diagnosed first saved time and prevented unnecessary parts replacement. The correlation between cold weather and worse performance was a helpful indicator that pointed to the intake air temperature sensor. Thanks again for helping me identify the problem and sharing your repair experiences.