could be a flat spot on the tps, so you're heading the right way there.
if possible have the fuel pressure tested. it also sounds like a bad fuel pressure problem, idk if your car has that fuel dampener thing in line but I've heard it goes bad and gives symptoms like that you are having.
a friend of mine had a GM cavalier and it hesitated but only at very slow cruising speeds somewhere around 30 to 38 mphs He had the fuel injectors cleaned professionally after spending a lot of $ on new parts that did not fixed the problem. so have the fuel system checked.
"All the Sorrows I've had to endure, I've entered the river , now all thoughts are pure and sacred"