I see from the picture that the throttle assembly is removed. Good.
Push the link back down and make sure it is straight (not twisted) on the end.
Also the passage (slot) can get filled with a little corrosion.
Spray a little penetrant inside and work the link up and down.

Notice the orientation of the small dust seal (metal and rubber part).
The need to know becomes apparent on reassembly.

"Adding CFM to a truck will only help at engine speeds you don't want to use."
"I found there was nothing to gain beyond 400 CFM."