Diagnostic Aids
WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
An intermittent condition could be caused by an improperly installed or damaged EVAP canister purge valve or a temporary blockage in EVAP canister purge valve. To repair a blockage in EVAP system perform fuel system cleaning.