The pot is right side of air meter box . (opposite eha ) It has a 3 pin plug, pull it out far enough to get the test leads on. I'm writing this from memory could be wrong. Put the car in KOEO put leads on Pin 1 and 2 . Voltage should be near 0. Deflect meter plate, at idle position the voltage should be .7volt as you push plate down voltage will go steadily up. I think voltage between 1 and 3 is around 5 volts.

I also did this test while monitoring eha current and discovered the current went to 0 when I deflected the plate to idle position.

There is a lot of good info on position pot in fouum.