http://chevroletforum.com/how-tos is the leading Chevy Silverado resource for technical guides. Simply put, when you step on the gas pedal, its position is sent to the ECM and then to the throttle position sensor. For the full step-by-step article, please visit http://chevroletforum.com/how-tos/a/chevrolet-silverado-1999-2006-how-to-replace-throttle-position-sensor-tps-392421

The TPS controls the position of the throttle plate and the amount of fuel injected into the cylinders, regulating the air-to-fuel ratio for proper combustion. Without a proper air and fuel mixture, your Silverado won’t reach its optimal engine performance and fuel economy. In effect, you should notice a rough idle, stalling, engine knock or misfires, and a hesitation on acceleration, all of which can be caused by a faulty TPS.

Replacing the throttle position sensor on your Silverado will only take twenty to thirty-five minutes to accomplish. It’s an easy job and will only cost the price of a new unit.

The supplies you’ll need are a flathead screwdriver, T20 Torx driver, and a 15 millimeter socket with ratchet.

Step 1 – Remove the Intake System

Remove the air intake hose. Use the flathead screwdriver to loosen the screws on the clamps.

Remove the intake assembly.

Step 2 – Remove the Throttle Position Sensor

Put the ratchet onto the tensioner and push it back enough to loosen up the serpentine belt. Loosen it enough so that the belt can be taken off the alternator.

Remove the bolt on the left side that is securing the alternator.

Loosen the bolt on the right only.

Using the flathead screwdriver, pry up the alternator.

This is the Throttle Position Sensor.

Disconnect the connector by pulling back on the tab.

Remove the throttle position sensor by taking out the two T20 Torx bolts.

Remove the sensor.

Step 3 – Install New Throttle Position Sensor

Line up the sensor and push it into place.

Reinsert the two T20 Torx bolts.

Hand tighten them first and then use the driver to tighten them the rest of the way.

Reconnect the sensor by pushing this clip back into place.

Push the wires out of the way. Push the alternator back down.

Reinsert the bolt and tighten it all the way up.

Tighten up the other bolt on the alternator.

Put the ratchet back on the tensioner, push it down and loop the serpentine belt back on the alternator correctly.

Reconnect the air intake assembly.

Tighten up the clamps with the flathead screwdriver.

With your new throttle position sensor, you can now enjoy the return of the responsiveness that your Silverado had from the factory.

source