My Jimmy seems to have poor response to the throttle. Idle is great until warm. Cruising speed throttle position is horrible.

 

What have you done to try to correct the issue? Tune up (plugs, wires, cap, rotor)? Any vacuum leaks?

Is this a full size or s-series truck? I need to know so I can move it to the appropriate section. Technical questions really do not belong in the General Chat section.