What does this do?? SOHC engine part

[outrun84]

I have a 97 SOHC and i was wondering what the heck this does. When you remove the cover to the engine that says "SOHC", you see the two air ducts on either side of the engine on top and in the center is a knob. It turns either way. What the hell is this knob? i have looked forever and dont know. My buddy decided he was going to screw with it and i need to know how to set it and/or what it does. HELP!

 

[aldive]

Can you post a picture of what you are referring to?

 

[Magicfan25]

is that knob on top of a silver cylinder? If so thats part of the IAC (idle air controler). I saw the knob when I had to replace mine, I messed with it for a minute and couldnt tell WTF it was doin. I didnt bother tryin to set it how I thought it might have been and I havent had any problems. Id say its fine and leave it be.

 

[Alec]

If it is a black knob that connects to a silver cylinder with a small wire harness, that's your IAC.

 

[outrun84]

hmmm yeah thats the one

Does anyone know the proper setting for it?? I have noticed that when it is turned one way or another the call will stumble or seem to lack power when coming from a start. But yeah it is the IAC.

 

[Alec]

The knob isn't really a setting, it just contains a small filter. I'd just "set" it so it can freely rotate either way.

 

[Robert]

As Alec said, the proper setting is anywhere you put it (that allows it to turn freely). If you were to pop it off you would find a small felt filter inside the black "knob". The black "knob" snaps on over a ridge on a 1/8" metal tubing line. There is no setting, it just holds the filter.