You have your pins assignments backwards. You are actually testing the Idle switch (pin 3) on the TPS against Pin 1(5v input) and it shows that it is working as it should. The circuit is suppose to open whenever the TPS is moved from a closed position. If you test that pin to ground(pin 4) it should have closer to 0 resistance at close and open when moved. To test the tps voltage, sweep the sensor while probing pins 2 and 4. You should see resistance increase from 0-4.5k+ ohms.