A good indication of a bad TPS is a sudden lose of power at a specific pedal position and engine RPM.
Using a DVOM(Digital Volt Ohm Meter), connect the negitive probe(black) to ground or battery negitive. The positive (red) probe to the signal(middle) wire.( wire 1 = 5 Volts = referance, wire 2 = .5 volts = signal , wire 3 = 0 volts = ground) Set the meter to DC volts and turn the key to the ON position.With the TPS connected,slowly open the throttle and watch the voltage on the meter climb from .5 volts to 4.5 Volts. any sudden drop or radicule change in readings indicates a bad sensor.
The problem with this method is that you can't see the voltage change over the time it takes to open the throttle. This is why a professional will use a labscope/oscilliscope. It has the ability to graph the changes over a period of time, which is the most accurate way to find a bad sensor.The technician will watch the arc on the graph, looking for the same results using the same setup.
There is no way to clean it, but it might be adjustable if the sensor has mounting slots.
to replace it is simply removing 2 or 3 bolts, if it is replaceable. If not, the whole throttle body unit will have to be replaced. Yours should be replaceable.
A.S.E. Advanced Automotive Engine Performance Technician