2000 town & country transmission issue? HELP

My wife has a 2000 t&c with 150k on it its a fwd with 3.8 and about a month ago while driving we noticed the rpms will jump up 400 and go back, with cruise control on or off being held at a consistent speed. and about for days ago it started shifting late. Still has all gears fluid looks o.k. and is full no check engine light . Im hearing transmission solenoid, tps sensor, input sensor, output sensor, tcm, iac, map, or egr are all possibilities or a rebuild . Or simple as a flush.. tonight i went out n started it it idles around 800 tried to hold it at 1200 and it would for a second and drop back to 800 with accelerator being slightly held. Not sure if related. Just observed it.. PLEASE HELP!

Was hoping someone more knowledgeable would jump on this but, here I am. It sounds engine related since you can see it stationary in your driveway. It sure sounds TPS related to me. Have you tested it?

Thanks for the reply!! I haven't checked it, I guess i was hoping someone experienced same issue. Ill start there then. Thanks