The throttle switch is an open close switch One portion works at idle and another at close to full throttle.
If you are talking about the airflow potentiometer then the best way to test is for voltage at the signal lead. The other two wires going to it are ground and the 5v signal wire. Idle should be around .8-1.0v going to 3+v at full range (check with engine at idle or with key on engine off with the sensor plate pushed all the way down.
Bosch Master, ASE Master, L1
33 years MB technician