When starting from cold the tickover seems a bit high. Once the engine is warmed up to normal operating temperature and if when driving one knocks the car out of gear instead of the revs dropping to approximately 700rpm tickover the revs increase steadily rising to 4000rpm and beyond probably if I allowed them; to. It does not always rise to 4000rpm but sometimes hovers around 2000rpm.

What could be causing the problem here?

1998 Focus Zetec 1.8 P 5-dr 89,000 miles from new

try disconnecting the idle control valve cable and see if the revs drop look to the right of the engine facing the car youll see the coil pack look down behind that and youll see the icv attatched with 3 bolts looks like this

I had this issue with my car (see info on left). It turned out to be a faulty auxiliary belt tensioner which needed replacing along with the belt.

Thanks guys for the info, I will investigate those points. One other thing, if I knock the car out of gear and coast to a stop, the engine revs should drop to tickover immediately but they remain at say 2000rpm. As I come to a halt the engine revs drop accordingly as the car slows down and are at normal tickover (about 700rpm) when the wheels have stopped turning and the car is stationary.

It might be worth checking the throttle position sensor. I had a similar problem on my car.

You may also need to clean/replace your idle control valve.

Thanks for the info, guys, working on it