Rough idling fiesta 1.4tdci

Hi,

I have a Fiesta Mk5 1.4 TDCi with 200,000 km.

I'm experiencing a rough idle when the engine is cold. Once the engine reaches operating temperature, the RPM stabilizes. This happens even when the ambient temperature is around 15°C.

There is another issue that is likely linked: when the engine is cold, if I rev it up and then brake hard, the RPM drops too low and the engine stalls.

Could you help me? Thanks!

p.s.

no error from the ecu