adjusting idle screw and running too rich..

[reddsm00]

hey, im having a problem with a really high idle...the car usually idles at 1200 to sometimes 1500 rpm and if im driving and i go into nutral the idle will not stop bouncing up and down until i come to a stop...then after about 10-15 seconds if im sitting at idle it will drop up and down again until i start moving...i was just wondering how to adjust the idle screw the right way...also im having a problem with running to rich, i installed a dejon tool air intake but i left the airbox off...could this be the problem? would putting the airbox back on fix it?

 

[slider85]

not a mechanic, but try making sure that your fuel filter is clean, fuel pump is wired correctly, and any other maitenance issues are done, then you can change the Idle Speed Controller. I think the best way to change your idle is to have a mechanic change the voltage in the ISC rather then turning the screw.

 

[steve]

What you have is called idle surge. It's caused by too much air at idle.
An improperly set BISS can cause it if your ISC is dead.
Check the coils in the ISC http://www.stealth316.com/2-isc-iac.htm
Clean your throttle body http://www.plymouthlaser.com/tbody.htm
Set your base idle speed http://www.plymouthlaser.com/biss.htm

If that doesn't fix it you need to look for vacuum leaks allowing air to bypass the throttle plate and check that your fast idle control valve is working correctly.

Steve