I am sure most of our Canadian friends have found a work around for this but in case you haven't...
Tip for Canadians using U.S. gas pumps
Canadian Seann Fox has another take on how to get U.S. gas pumps to recognize Canada-issued charge cards: He's given his credit card companies a U.S. mailing address (one where he'll be at sometime in his travels), then uses that U.S. ZIP code at the pump. "Works 85 percent of the time," says Seann. Thanks for the zippy tip, Seann!