Possible problem?

I have a golf fitted with a 1900 TSR 8v engine, it starts fine in the mornings everytime and has never caused a problem but ever since I bought it, the car seems to idle high when cold, almost as if the revs are sticking at around 2000rpm instead of settling down to normal idle. It does not always do it, but about 8 times from 10 it will. After its been driven for a bit, the problem seems to go away, and even when the problem is there - it can sometimes be normal.

Is this an easy fix, does something need cleaning or replacing?

Thanks.