Throttle Position Sensor (TPS) Test: 
To test the TPS 
Ignition OFF, Ground Pin #3 and monitor Pin #1 with a 12V LED (+lead to Battery + and -lead to Pin#1). Ignition ON, Engine OFF (Pin #3 should remain grounded during this test) 
The Test LED will be ON at idle (closed throttle) and OFF just above idle. You should also be able to watch the temperature warning lamp on the tachometer blink ON at idle and OFF just above idle. 
Pin #1 should be Low at idle and High just above idle. In other words, if you are measuring from ground to Pin #1 with a voltmeter, Idle should be close to 0 Volts and just above Idle should be close to 12 Volts. (This test also works for Oilheads (1994-2001) with Motronic 2.2 Engine control Units but since there is no temperature warning lamp, you must use either a voltmeter or a Test LED as described above). 

NOTE: Measuring the voltage between pins 1 and 4 at the TPS connector should indicate 
0.375 Volts at the idle setting (closed throttle) with ignition ON engine OFF. 
Snap the throttle open/closed a few times to ensure a consistent reading. To adjust the TPS, loosen the two screws slightly and rotate the TPS until the temperature warning lamp (or the Test LED) 'just' comes ON at idle and goes OFF just above idle. If you are using a voltmeter, adjust the voltage to 0.375 at idle (closed throttle). This voltage MUST remain below 0.400 Volts at idle.