high idle at startup?

Ok, I just got my civic going after being broke down for what seems like forever. I replaced the head gasket and everything seems fine, smokes a bit, but i really don't care cuz of the way gas prices are now. I was driving an old ford truck with about 10 mpg, so you can see my reasoning. Ok, when I start up the civic, it is idling really high, but if i pop the gas pedal, it's back to normal. Happens on most starts. What could be causing this? Thanks.

your engine is cold and its warming up. lol.

umm, no, that's not it, it has never done this until recently. And when i say idling high, i'm talking well above 2000 rpms, not sure the exact number though, no tach.

Eacv on back of intake manifold. try cleaning it inside with car/throttle body clean. see if that helps