Down shift and punch it brings the engine to 1k rpm then rough idle.

What is your question?

5th to 3rd punch it, drops right to 1000 rpm. It doesn't recover. I pull over and it idles rough up and down. It will run like this till I shut it off. Start it back up everything's fine. Seems like a sensor to me but I don't have a clue beyond that. If anyone else had this issue I would appreciate any info.