[SkinnyG]

That's the detent cable.

There's a square sort of clippy thing in the plastic right behind the bracket at the intake manifold. Pull it up so it "unclips" the cable.

With the detent cable unclipped, push the throttle to WIDE OPEN. Holding the throttle wide open, push the square clippy thing back in so it locks the cable at that adjustment.

Boom. You're done.

There will be some slack such that the detent cable does not even move until somewhere close to half throttle. That's normal.