I HAVE A CODE P0442, 2001 CHEVROLET SILVERADO 1500
The P0442 code is for the evaporative small leak. You should start by inspecting the gas cap. If the cap is loose retight the cap and clear the code. If the gas cap seal is damage, replaced the cap and clear the code.
More information: http://engine-codes.com/p0442_chevrolet.html