The past couple days I noticed that when I start my car when it's cold the idle wants to stay at between 500-750rpm. before it would go up to 2000rpm until it warmed up then go idle back to normal- 5-750rpm. I am having to hold the gas pedal to warm it up or else the low idle will cause it to stumble and want to die.
Its a B16a head, intake mani., gsr block.
Is there some sort of valve that lets air in past the throttle body to bring the idle higher during warm up?
Is it stuck open or closed?
How can I fix this?
thanks if anyone can help.

 

yes there is a valve right on the back of the manifold by the throttle body. It has two 10 mm bolts holding it on and two coolant lines running to the bottom of it. Its called the IACV (Idle Air Control Valve). It looks like a sideways cylinder sort of maybe about 3-4 inches long. Take it off and there is a screen that sometimes gets clogged. Give it a good cleaning and go from there.