Idle adjust how do I adjust the idle on my engine

most older cars had 2 adjustments , a air screw for enrichment and throttle screw for engine idle speed, later models did away with the enrichment screw, to adjust set idle screw to 600 rpm, adjust air mixture screw to fastest rpm , reset idle screw to preferred idle speed.

Most older cars had 2 adjustments , a air screw for enrichment and throttle screw for engine idle speed, later models did away with the enrichment screw, to adjust set idle screw to 600 rpm, adjust air mixture screw to fastest rpm , reset idle screw to preferred idle speed.

You can't adjust the idle , There is a minimum idle adjustment set at the factory , you don't want to mess with that . The PCM / ECM ,engine computer controls the idle speed by the idle air control valve (motor) . You may have a dirty throttle plate mess with the base idle .Check out this video on ford base idle adjustment . Some one who didn't know cranked up the base idle causing problems Ford IAC valve test how to adjust minimum idle speed

Its not really adjustable.
The computer controls idle speed via the idle air control valve.
You probably have a vac leak.

You probably need to adjust idle speed

An IAC (idle air control) motor is designed to adjust the engine idle RPM speed by opening and closing an air bypass passage inside the throttle body. The cars computer or ECM (electronic control module) receives information from various sensors and will output signals to adjust the IAC motor in or out to adjust engine idle speed by controlling engine idle air. ----------------------------------------------------------------------------------------
XPROG-M V5.0

Right now look at the front of the engine behind the exhaust manifold and their are two breather pipes connected to a T connection that comes from the engine and check these pipes as if perished and split the engine will not idle .You cannot adjust anything without a dealer software to reset the mapping so check these pipes first and iam sure you will find their split and gone soft

Idle Speed Control (ISC) Motor OPERATION Eagle Throttle Body Fuel Injection (TBI) System NOTE: The Eagle TBI system is used only on 2.5L Premier engines. The Idle Speed Control (ISC) motor is mounted to the throttle body and controlled by the PCM. The throttle lever rests against the initial adjustment screw of the actuator (plunger). The idle speed is not adjustable. The initial adjustment screw is only used to establish the initial positioning of the actuator when the ISC motor has been replaced. The actuator extends or retracts to control engine idle speed and to set throttle stop angle during deceleration. Based on inputs from the various engine control system sensors and switches to the PCM supplies current to the ISC motor to adjust the actuator position for the particular operating conditions.
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Here are some images that might help to assist you, and let me know if you require any further assistance.


Adjust the curb idle with the engine warmed up and the choke off.




The air/fuel mixture screws should be adjusted with the engine warmed up and at normal idle speed, then turn each air/fuel mixture screw in one at a time until the engine just begins to mis-fire, then back the air/fuel mixture screw out 1-1/2 to 2 turns out a half a turn at a time until the engine idle is the smoothest. (your vehicle might have restrictor caps over the air/fuel mixture screws to limit the amount of adjustment)






The choke adjustments;






To adjust the vacuum tension pull on the choke pull-off:





Adjust the fast idle screw to the proper RPM with the engine cold and the choke on.

On any carburator,one screw is for the idle speed, the other the air/fuel mix.Start the engine and let it get plenty warmed up. Adjust the idle screw to make the engine run slow. Turn the air/fuel screw in until the engine starts to die then out till it starts running loady.You want the screw between these two locations. Adjust it till the engine runs the fastest. Now adjust the idle speed screw to about 1000 RPM.
I hope this helps you.