Its not incredibly common but here's a thought!
Unplug you TPS and see what happens
From there plug it back in and your TPS should be reading .07-8 at idle if I recall (you mentioned it happened when sitting). I would then if confirmed that is not reading correctly ( higher than .07-.08v at idle) look at the actual TB rod, would bet you have a flat spot and rod needs adjusting... You see if the reading is higher it has to have gotten that reading from somewhere
So adjust the rod angle or new TB, either way and retest v output.
Again just a shot in the dark but if all the obvious first things don't pan out, take a look. GL hope is something simple.