Tomclancy

Ok so heres my issue. Ive searched alot of different forums, and still stumped so figured i would ask in my own thread.

I have a 2000 civic dx that blew the head gasket. I replaced the head gasket, got the head machined and no problems with the head compression still good.

After putting everything back together and plugged in, crank the car and it runs fine at normal idle for bout 5 mins. At first it would rev high then go down to normal. So i shut it off and unplugged the battery for a few days cuz i got busy with work. Came home today and plugged the battery in, and cranked the car, ran fine for bout 5 mins, then drops idle and comes back up.

Ive read that it could b alot of things, like a bad IACV or that i need to do an idle relearn. How long should i let it keep going up and down? im not an expert at engines but i know my way around them. this is my first complete tear down to the block and i had another guy help me that knows hondas pretty well but he cant figure it out.

Anyone got any ideas that i could try out? or steps on how to relearn idle?