High idle

[liona]

Hello!
I also have a high idle problem. I was trying to locate and pinpoint the "air screw" or "idle adjuster screw" being referred to in this thread. There's a hole (with metal plug) on top of the intake manifold near the hose connecting to the 3000 pipe. I thought it might be that, if the screw is under the plug. Not being sure I got it right, I was reluctant to remove the metal plug. Could someone pls help with picture or further description to locate this "idle adjuster screw"?
Also, how could I test or check if the ISC is bad? Is there a part, like a valve or something that can be replaced in the ISC without replacing the whole ISC assembly? I would really appreciate any further advice or help to fix the high idle. Thank you.