Fuel pump/gas pedal stick

In the last few months when I start the van up & first step on the gas pedal, it hesitates to move for a few seconds then jumps to go forward. Recently, I took it on a trip that had mountains and on the steep inclines, it was continually skip like it wasn’t getting the gas it needed to go. Why do you think is it doing this? Is this an expensive fix?

The throttle plate sometimes get gunked up and sticks in the closed position. A good choke cleaner should help. As for the “skipping” I do not have a comment.