American Honda Motor Co. said it has fired its public relations agency after 15 years, for what the Torrance-based car manufacturer described as an "unbecoming, underhanded act." Honda terminated Fleishman Hillard after learning that the St. Louis-based agency had made a bid for the account of the American Automobile Manufacturers Assn., a Washington, D.C.-based trade organization that represents domestic auto makers. Several years ago the organization tossed out American Honda, which often was at odds with Big Three auto manufacturers over trade issues involving Japan. "At the same time Fleishman Hillard was pitching the AAMA, we were considering a pitch from their L.A. office to double the size of the [American Honda] account," American Honda Public Relations Manager Art Garner said. Fleishman Executive Vice President Bill Anderson in St. Louis said his agency "wishes Honda every success as they go forward. Honda is a very good company."