Engine idles high

I have a 2002 Mazda 626 4 cylinder 2.0 with about 46000 miles on it.When I first start it up after its been sitting for at least 6-8 hours its very loud and idles high at about 2 and 1/2.Then after it warms up after about 5 minutes the idling gradually goes down to about 1 and 1/2 where it should be and is nice and quiet.If the car is sitting for only a bit,it doesnt do this as much,maybe only for a couple of seconds depending on how long its been sitting.But when its been sitting for a while its quite loud.
If I drive it right after I start it up after its been sitting ,it seems to take the loudness away.

Thanks,Ryan of Cortland NY