Quote Originally Posted by 97_gq_lwb View Post
That is idle adjustment pull it outward to up the idle then clockwise to lock it in position.
Anticlockwise to unlock it and let it go back in.
Handy when warming up the engine or when tackling rough stuff off road once locked you can keep a slow steady speed without touching the accelerator pedal
It is NOT your CRUISE CONTROL knob. Did your truck come with an owner's manual?

Rossco