What is a throttle plate? On a Chevy Cavalier Z24 ?

Question

It is a year 2001

what is the purpose of cleaning it ?

Answer 1

A throttle plate is the part of the air/fuel induction system that controls how much air is allowed into the engine.

The throttle plate is round, encased in the throttle body (which you can think of as a tube, the same diameter as the throttle plate).  The throttle plate is on a shaft going across the throttle opening, and can be rotated (using the accellerator pedal) parallel or perpendicular to the airflow through the throttle body.  When it is perpendicular to the airflow, the engine is at idle.  When it's parallel to the airflow, and not covered with carbon buildup, the engine is at Wide Open Throttle (sometimes abbreviated WOT).

It is helpful to clean the carbon buildup off it so that Wide Open Throttle really is Wide Open, so you get the maximum power possible.  I guess in theory you could get carbon making it stick open a little giving you a high idle speed, but I haven't seen that happen.

With a Chevy Cavalier, you're going to need all the power you can get out of it, but as long as the carbon buildup isn't too thick (i.e., sheet of paper), it won't make much difference.

To clean it, you'll need to put a brick on the gas pedal (with the engine off, of course!), because the inside (closest to the engine) is going to be the sootiest.  Use an aerosol carburetor cleaner and some throwaway rags or towels.