How do you repair OBDII code P0442 on a 2003 Chevy Blazer?

A code P0442 most likely means one or more of the following has happened: * A loose or improperly affixed gas cap * A non-conforming gas cap (i.e. not factory/original brand) * A small leak/hole in a fuel vapor hose/tube * Other small leak in EVAP system * Faulty vent o-ring seal

With a P0442, the most common repair is to: * Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back. * Otherwise, replace the gas cap, or * Inspect the EVAP system for cuts/holes in tubes/hoses