On the driver's side of the F 150 carb, there should be the linkage for the throttle. On the linkage there should be a set screw that you can turn to adjust the engine idle.
probably a bad idle air controller.
Most likely computer controlled and not adjustable
Idle is computer controlled and is not adjustable.
You can not adjust the idle screw, it is sealed off at the factory. If you are having a high idle problem check for a vacuum leak or a bad idle air control valve. These will commonly cause a high idle.
At the base of the carburetor are 2 screws. One adjusts the idle speed and the other adjusts the idle mixture. Screw the idle mixture in until the engine starts missing then screw it out 1 turn. Then, adjust the idle speed screw to about 850 RPM.
You adjust idle with idle timing
To adjust the idle on a 1984 Mercury Capri, first ensure the engine is at operating temperature. Locate the idle adjustment screw on the throttle body; this is typically a flathead screw. Turn the screw clockwise to increase the idle speed or counterclockwise to decrease it, aiming for the recommended RPM specified in the owner's manual. Finally, check the idle speed using a tachometer and make any necessary fine adjustments.
Adjust idle on Mitsubishi diamante
how to adjust idle on 2001 legacy
you can adjust it via the idle control valve.
The IAC valve is on the back of the throttle body. It has 2 bolts on the back of it and a black cylinder on one end. The idle adjuster screw is on the front of the intake and has a couple cables running to it. Let your car fully warm up and turn the screw to adjust the idle.
you cant adjust your idle, it is computer controlled