To figure out what sensor is actually needed, you'll need to:
* Get the exact diagnostic trouble code (DTC): This code will tell you precisely which sensor is malfunctioning.
* Consult a repair manual: A Haynes or Chilton manual specific to your 1996 Chevy Silverado's engine (e.g., 4.3L, 5.0L, 5.7L) will show the location of all the oxygen sensors.
* Use a wiring diagram: This will show the sensor's location relative to the wiring harness.
Without the DTC or a specific sensor number from your repair manual, determining the location of a non-existent "Bank 1 Sensor 3" is impossible.