To replace an idle arm, first, ensure the vehicle is safely lifted and supported on jack stands. Remove any necessary components that obstruct access, such as the wheel or suspension parts. Unbolt the old idle arm from its mounting points, then install the new idle arm in reverse order, ensuring all fasteners are tightened to the manufacturer's specifications. Finally, align and check the vehicle's steering and suspension for proper function before taking it for a test drive.
You will need a special tool called a "fork" that pops the connection. Remove the nut at the end of the idle arm joint then put the fork in place and give it a few good hits with a big hammer. Of course you will complete the destruction of the idle arm, but you're replacing it anyway. After the joint is loose, remove the bolts from the frame and drop the idle arm and replace it.
Simply replace them. Make sure the pitman arm is bad before replacing it.
The cost to replace an idle arm can vary significantly depending on the make and model of the vehicle, as well as labor costs in your area. Generally, the parts alone can range from $50 to $200, while total replacement costs, including labor, might range from $150 to $500. It's always best to get a quote from a trusted mechanic for the most accurate estimate.
there is an "idler arm", its part of the steering and runs horizontal, as well as a pitman arm
check your pitman arm and idle arm
There is more than likely a problem with the idle arm censor that would cause this. There may also be a problem with the throttle body.
replace it
The pointed end of the idle speed screw should be centered on the idle arm on the carburetor. http://store.chainsawr.com/
You need to clean (or replace - $200) the idle air valve.
clean or replace your idle air control valve.
Currently it seems like you have no choice but to replace the complete arm, that is all I can find available.
loose rocker arm[s]