GM Repair Problems? Ask GM Repair Expert Now.
Really the only thing that will set a reduced power message in your truck is the throttle body, there is two sensorsin it and they aren't seeing correlation, clean the connector at it thoroughly, tighten the pin tension and make sure the wires aren't corroded at the connector, perform a global reset( disconnect the battery and touch the cables) then retest and see if your issue is still present. There was a lot of problems with those throttle bodies and the electrical connectors at them.
Keep me posted.