RIVERSIDE, Calif. -

 The average price of a gallon of self-serve regular gasoline in the Inland Empire rose 2.4 cents Friday, its largest daily increase since Sept. 14.

   The average price in Riverside and San Bernardino counties has risen 11 consecutive days to $3.741, its highest amount since Oct. 23, according to figures from the AAA and Oil Price Information Service.

   The average price has risen 14.2 cents over the past 11 days and is 12.1 cents more than one week ago and 8.5 cents higher than one month ago but 42.9 cents less than one year ago.

   The rising prices are the result of annual refinery maintenance season when supplies of the winter blend gasoline drop as refineries start production of the more expensive summer blend, according to the Automobile Club of Southern California.