fiesta (endura-e) over revving

make: Ford
model: Fiesta MK4
year: 1998
mileage: 80 000
engine: 1300 cc, endura-e (same as in KA)

I have a problem with the engine overrevving when pressing the clutch, it appears rarely but it seems that it gets worse when driving for a long time...

It seems that it's a very common problem with that engine but after lot of googleing i didn't find a clear solution. Here i what I found as the possible causes:

1.throttle position sensor.(t.p.s.)
2.engine coolant sensor.(e.c.t.)
3.idle air control.(i.a.c.)
4.some models-maf,or map sensors.
5.e.c.u.
6. Clutch switch

But it must be only one of theese...


Thanks.