Hard to determine throttle position sensor condition - without looking at it. It may seem to function fine using an ohmmeter, but like most electronics with mechanical/moving parts, it is prone to wear.
Because one portion of the TPS is designed to rotate while the other portion is stationary, some TPSs may seem a bit more sloppy than others. This situation may be analogous to worn throttle shafts or the rotating vacuum advance/retard plate upon which the ignition points are fixed. I suppose the best advice is to minimize the movement by keeping things clean and slightly lubricated. The circuitry may have some gold plating and the working elements may be protected from the elements. Still, it doesn't take much to penetrate the protective barrier. Pressure washing is probably
not the best idea, unless you need an excuse to replace electronics.
When I mentioned full throttle movement, I was thinking that maybe something with the throttle linkage was preventing full throttle movement. I haven't looked at a djet TPS in a long while, but I always thought the "clicks" emanated from the TPS, itself. An injector that fails to "click" and move its pintle, is something else.
Gratuitous pintle pictures
Interesting negative camber
Will it fit.
Will it float
Murray