I have been having problems for many months with an intermittent high idling speed problem.
At times it has become quite scary with the car reving at 3.5K at junctions and also pulling
the car along when at speed. Also when changing gear the revs go up instead of down!!
The Idle Control Valve has been cleaned out many times and replaced once.
I was getting desperate until I read somewhere about the benefits of WD40. So I sprayed
all the electrical connectors visible in the engine bay and guess what I haven't had a problem since.
Thought this tale may be of help.

As I started to read your post I thought that I'd advise spraying all the linkages around the throttle.

Then I read on and that was exactly the solution. Always nice when that works (free). I tried it on the father-in-law's Civic last summer and it didn't help. Of course it was just a one-off deal. Might have had more luck if I'd had the car for longer.

Thanks for sharing a solution that worked. Just as important as posting a question and getting help.