my95wrx idleing high problem?

Anyone know what this could be, My scooby is idleing a bit high, 1200rpm. Yesterday when slowing down after a spin it seemed to idele at 1500rpm for a minute or so.

someone suggested to take off the idle speed control valve and give it a wash out with WD40.....anybody got any other suggestions or ideas of what it could be.....

thanks

more than likely the icv alright. if youre looking into the engine bay its to the right of the throttle housing on the manifold. think its 2 x 12mm bolts, 2 x water hose and a breather pipe.