Could be as simple as idle adjustment, but, before you go turning any screws you have to recognize that CIS is comprised of a bunch of components that all work together as a system. Adjusting one component blindly can lead to adverse effects. So, your high idle could be a stuck Auxiliary Air Valve which could be overcome by adjusting the idle way down, but the car would then run lean (bad). So, what do you do? Testing! Get a cheap fuel pressure gauge ($50 JC Whitney) and test the system and control pressures to make sure they are in spec first (spec is in the bentley). You can test the AAV by sticking it in the freezer and applying 12V. Vacuum leaks (also a potential high idle contributor) can be found using an unlit propane torch with the car running around potential leak points. There is a test for every component in the CIS system.
Problem with CIS is it is a system. The component replacement strategy doesn't work - someone says "sounds like the WUR" or "must be AAV" and you spend large $$ chasing the parts. Test, make small changes to one component at a time, re-test, rinse, repeat...
BTW - this will be helpful for you:
http://members.rennlist.com/jimwms/CIS/CIShome.html