Gasoline and diesel prices in the Golden State may soar to fresh records in coming weeks as one of the largest refineries on the West Coast starts maintenance. Chevron Corp. is scheduled to carry out multi-unit maintenance at its Richmond refinery on San Francisco Bay, which is expected to last for about a month, according to people familiar with operations. The planned work includes gasoline-making units and comes as both Phillips 66 and PBF Energy are already conducting upkeep at diesel and jet fuel-making facilities. California gasoline pump prices remain far above the national average at $6.435 a gallon, according to auto club AAA. In Napa, the most expensive metro area in the country as of Tuesday, prices are as high as $6.63 a gallon. The national average is $5.01 a gallon. Retail prices have soared even as stockpiles have remained ample so far this season. At 31.4 million […]