Costco Wholesale reported another quarter of solid growth. Yet the numbers tell a more nuanced story about American consumers. Record gasoline volumes at the retailer’s pumps point to heightened price sensitivity. Shoppers are filling tanks in unusually high numbers. They seek savings of 10 to 30 cents a gallon. The company’s fiscal third-quarter results, released late on May 28, showed net sales rising 11.6 percent to $69.15 billion. Net income climbed to $2.19 billion, or $4.93 a share. Comparable sales grew 9.8 percent overall and 6.6 percent when adjusted for gasoline prices and currency swings. Digital sales jumped more than 20 percent. Costco investor relations release . But the standout detail came from the fuel business. CEO Ron Vachris described “record-breaking” gasoline sales. Pumps needed extra deliveries to stay stocked.…