I have a Fiesta 2000.A good car with no problems,except this last year the engine when I slowed or came to a stop would rev very high,at first I thought it was the accelerator sticking.When I checked no it seemed okay.This did not happen every time I drove it ,just occasionally, then more regular. I replaced the accelerator cable and it seemed okay,a little slow dropping the revs but it was better than previous.Then it started again. I took it to a local garage,had it serviced and a new cable...everything was fine for a month or so ,now it has started again, I am thinking now it is the automatic choke. Any technically minded people can advise please

 

These have a little sensor in the power steering pipework (sometimes behind the front bumper, to the right, looks like a little metal cylinder screwed into the pipe at a 90 degree angle) with a beige plug (I believe) these are prone to the wires breaking, if this has happened, it can cause the high revving you describe. Also the ISCV (Idle Speed Control Valve) can cause it, clean it out with some carb cleaner and see if it helps.

 

Thanks Sam, but my car does not have power steering,it is left hand drive as I live in Mexico