Check engine light comes on frequently with code PO455. on 2005 Buick Park Avenue

It's not the gas cap. Could changing the Canister Purge Valve solve the problem? I reset the code about 4 times per tankful of gas.

Asked by for the 2005 Buick Park Avenue
these can be very involved and exp to guess, i rec you have it ck'd by a good mech and save time and $