The average price at the pump for a gallon of gasoline is dropping, but the average price at the pump for a gallon of diesel is climbing. The Dept. of Energy said this morning that the average diesel price rose 3.8 cents to $1.483 gal. The price is 5.4 cents higher than it was on Sept. 29, but a fraction lower than it was on Sept. 8, when it hit $1.488. According to nationwide gasoline price data compiled by the Oil Price Information Service (OPIS) for AAA, the average price of self-serve regular gasoline has dropped 12.4 cents per gallon since mid-September and averages just over $1.56 per gallon. AAA noted that gasoline prices increased sharply at the end of August due to higher crude oil prices, rising demand for gasoline, a drop in gasoline imports and a series of problems with domestic gasoline refineries as well as a pipeline break.