On a 1993 Chevy 1500 with the 4.3L V6 engine, the Throttle Position Sensor (TPS) is located on the throttle body. The throttle body itself is mounted on the intake manifold. It's a small sensor, usually with a single electrical connector, mounted on the side of the throttle body. You'll see the throttle cable connected to the throttle plate; the TPS is typically nearby.
It's easiest to see it from the top of the engine bay, but you might need to maneuver to get a clear view. A flashlight and possibly a small mirror will help.
