Maintenance at U.S. refineries and a shift to a more expensive summer blend of gasoline is leading to a spike in retail gas prices, motor club AAA reports. AAA reports a national average retail price for a gallon of regular unleaded gasoline at $2.33 for Tuesday, up a fraction of a percent from the previous day and 2 percent higher than last week. Gas prices have been relatively stable in recent weeks as a late winter drop in crude oil prices kept some of the pressure off consumers. Retail prices, however, have increased seven of the last eight days. “Although the increase in prices has been moderate, it is possible this trend could continue as […]