hey phobia, 3 grand rpm idle = im quite sure your throttle cable isnt so tight that it moved the throttle body just a tade and are you positive you dont have a vaccum leak anywhere on your rig? one of my friends (92 civic ex, idle'd at 2500 after removing his turbo = turns out the vaccum lines the boost guage went into was open for business). pluggin the bottom of it, do you mean you plugged the 2 holesunder that thingie that allows the coolant to flow through? yes, all it takes is carb cleaner, preferably anything in relation to carb cleaner that will eat through gunk as you spray it, but after you reinstall the sensor assembly your car will be a little funny on starting until it burns all that junk off. if your positive its nothing but that vavle, maybe your car is doing that high idle because you blocked the coolant lines to ensure the vavle wont work anymore. try and un block them, return the vavle to normal operation and let us know what happens.