Do you know what causes power loss in Ford Fiesta?
When I press the accelerator on my Y reg. Ford Fiesta there is no power, the car will drive slowly. The engine just revs up and goes at it's own slow pace
If the engine revs up but the car does not go faster then your clutch is slipping.
It may just need adjusted but probably needs a new clutch fitted.
If you keep driving the car it will very quickly get worse and fail completely, leaving you stranded.