V90 Stalling at Idle

I had a similar issue with my old BMW 5 series a few years back. Symptoms sound almost identical. The idle was all over the place, and the engine would occasionally stall at traffic lights. Have you checked the throttle body for excessive carbon buildup? That was the culprit in my case.

Throttle body, eh? Interesting. I hadn't gotten that far down the rabbit hole yet. Was it visibly gunked up when you checked it, or did you need to remove it to really see the extent of the problem?

On the BMW, it was quite apparent upon visual inspection once the air intake was removed. However, a thorough cleaning often requires removing the throttle body for proper access. Given the symptoms and error code, it would be prudent to have a workshop inspect the system. The error memory may contain some additional information to guide the diagnosis.

Thanks for the tip! Took it to my local mechanic, and you nailed it. The throttle body was indeed caked in carbon. Ended up replacing the IAC valve as well, as the mechanic recommended. Cost me 425€, but the car runs like new again. Really appreciate the help!