Kentucky Governor Steve Beshear and other officials have announced an investigation into why gas is more expensive in Louisville than in the rest of the state.The governor says he’ll work with Attorney General Jack Conway and Louisville Mayor Jerry Abramson to investigate why motorists in the metro area are being charged up to 40 cents more a gallon.Abramson acknowledges that Louisville prices should be slightly higher because motorists are required to use the cleaner-burning reformulated gasoline, or RFG.“For years when people would say, ‘You know, it’s a little cheaper out here or out there in surrounding counties or over in southern Indiana,’ people would say, ‘Well, it’s because of RFG.’" said Abramson. "Well when you look and compare Louisville to RFG instituted in Northern Kentucky, we’re still 18 cents higher.”The investigation will start this week. Beshear says he’s not accusing anyone of price gouging or collusion, but wants some answers from suppliers and retailers.A call to the Kentucky Petroleum Marketers Association was not immediately returned.