Not Quite Right

Since I had my lower intake manifold gasket fixed by the dealer last week, the truck just doesn't seem to run like it used to. It seems like it has lost power/response. It is not dramatic but just enough to notice. The truck runs fine otherwise. Is there anything that could have happened while being fixed that the mechanic didn't notice or adjust back to where it was originally?
Ken

If the battery was disconnected then the computer reset itself. If any mods were done to the engine then the computer will need some time to adjust to these modifications and your driving habits. I've heard sometimes it needs several hundred miles.