My idle control valve is messing about on a Nissan Almera GTI I bought last week as my work car and to take the dogs out and about in. It was idling at 1,700rpm. I have done the timing, new HT leads, plugs, vac pipes checked and still idle'd high....... so I took the plug off the ICV to see what happened.......revs went from 1,700 to 900rpm, very happy!! Thing is........is it ok to drive about without an idle control valve plugged in, could there be any dangers to engine, more petrol used, less performance etc??