To test the TPS use a voltmeter (analog is better that digital for this) check for voltage (key on-engine off) between the black(ground) wire and the grey (signal) wire.
use pins to penetrate the wires so you can leave the connector on the TPS

As you operate the throttle the voltage should climb from .5v to 5.0v steadily
Operate the throttle very slowly, the needle on the volt meter should climb steady with no little bumps or drops