Fiesta engine stalls at idle

I had similar symptoms with my Fiesta. It could be the purge valve. This valve is part of the emission control system and regulates air flow from the fuel tank to the engine. When it fails, it can cause a vacuum leak, leading to a check engine light and stalling. Did you check for any codes related to the purge valve or EVAP system?

Thanks! I did check the error codes, and it pointed towards a leak in the fuel tank ventilation system. Is the purge valve replacement something I could do myself, or is it more complicated?

A leak in the fuel tank ventilation system can definitely cause those issues. If the error code mentions a specific leak in the system, like a defective activated charcoal filter, then that is likely the culprit, not only the purge valve. While replacing the purge valve itself can be straightforward, diagnosing the exact source of a ventilation leak can be tricky. I would suggest taking it to a trusted workshop. I had to pay 275€ to get mine fixed.

Thanks for the advice! I took it to a workshop, and it turned out to be a defective activated charcoal filter, just as suspected. They replaced it, and the stalling issue is gone, and the check engine light is off. Appreciate the help!