Fiesta engine running roughly

I had similar symptoms with my Fiesta. Have you checked the spark plugs or the oxygen sensor? Could even be the mass airflow sensor. Does the check engine light come on immediately after you start the engine?

Thanks for your quick reply! I haven't checked those specifically yet. I was hoping it was something simple. Yes, the check engine light comes on almost immediately after starting. Could a defective injector really cause all these problems? That seems significant.

Yes, a defective injector can definitely cause all those symptoms, the rough running and stalling especially. Given the check engine light illuminates so quickly, I'd suggest getting it properly diagnosed at a workshop. They can pinpoint which injector is faulty. I think it is worth it.

Thank you so much for the advice! I took it to a workshop, and you were right – it was a defective fuel injector. They replaced it, and it cost me 515€. The car is running smoothly again. I really appreciate your help!