The combination of a weak economic backdrop, sell-off in global stock markets and gains in the US Dollar were forces pressuring September RBOB this morning. It is possible that RBOB prices slumped after EIA data showed US gasoline prices falling for their second week in a row. The agency pegged US retail gasoline prices at $3.60 per gallon, down $0.07 on the week. Meanwhile, some traders suggested that refinery challenges in Memphis and reduced inventories in the Southeast and gulf regions might be forces limiting weakness this morning.