Revs not falling
I’ve just bought a 55-plate Ford Fiesta 1.25 16v petrol manual with 114,000 miles. The engine is as sweet as a nut and has been well serviced. However, whenever I change up a gear, the revs do not fall quickly enough to make a smooth gearchange. I have to wait a couple of seconds for the revs to fall before selecting a higher gear. I have tried changing the plugs and air filter, to no avail. Russell Munn The most likely cause of the revs staying too high when changing gear is that the idle control valve is sticking. This can be a common problem on the 1.25 engine and I would first try to clean the valve out using a carb cleaner aerosol.
It would also be advisable to check the inlet manifold and vacuum pipes for any air leaks, although if this were the problem I would expect further symptoms to show up. You should also check the wiring loom on the engine and inspect the connecting plugs to the ICV and TPS. If this does not help, you may need a new idle control valve or throttle position sensor. Using a code reader may highlight the problem and help narrow the source of the problem.
The idle control valve.