S80 rough idle and check engine light

Whoa, sounds familiar! I had almost the EXACT same thing happen on my S80, though I can't remember the exact mileage. Check Engine light was on, car felt sluggish, and yeah, that rough idling was super annoying. Did you actually check the temperature reading from the sensor with your diagnostic tool? Like, is it giving you crazy numbers?

I did scrutinize the temperature readings via the diagnostic interface. The values appear erratic and incongruous with ambient conditions, solidifying my suspicion of a defective sensor. Did replacing the intake air temperature sensor resolve the issues you experienced?

Totally fixed it! After swapping the sensor everything went back to normal. Though, honestly, if the temperature readings are jumping all over the place, I'd just bite the bullet and get it done at a shop. Those sensors can be tricky to get to sometimes, and you don't want to mess anything else up. Better safe than sorry, you know?

Following your suggestion and my own assessment, I entrusted the repair to a reputable workshop. The intake air temperature sensor was indeed the culprit, its replacement costing 155€. The symptoms have vanished, and the Volvo now runs smoothly. Case closed.