I have a 90 Accord EX and when I first start it up when it is cold, I get an Idle that goes from 1000rpm all the way up to 3000rpm then down and repeats. It does this repeatedly until the car warms up, very annoying! I have looked into it, and have a clue of what causes this, but I wanted to ask you guys. I think it does this because of any of the following, air pockets in the cooling system, vacuum leaks, FITV, IACV, Head Gasket, and more....Thanks for any help, I think I am going to start with the cooling system and then check the FITV/IACV....Thanks for any help....

 

again,,,,,,,,,,search our DIY section there are write ups about this issue