A gallon of gas costs 4.60 in U.S. ; it costs $ about $ 3.10 north of the border . TIJUANA warns short-term savings could spiral into long-term expenses . That fuel mixture can ruin the emission control equipment on American cars and cause them to fail emissions tests . Mexican gas containis more sulfur -- which could hurt Tijuana cars .
A gallon of gas costs 4.60 in U.S. ; it costs $ about $ 3.10 north of the border . TIJUANA warns short-term savings could spiral into long-term expenses . Mexican gas containis more sulfur -- which could hurt Tijuana cars .