The average price of a gallon of self-serve regular gasoline in the Inland Empire dropped four-tenths of a cent Friday to $4.28, one day after rising one-tenth of a cent.

   The average price in Riverside and San Bernardino counties is 1.5 cents more than a week ago, 25.3 cents higher than one month ago and 40.9 cents greater than what it was one year ago, according to figures from the AAA and Oil Price Information Service.

   ``It's hard to say when local prices will come down because wholesale prices remain high due to continued supply issues coupled with increased demand  for fuel,'' said Jeffrey Spring of the Automobile Club of Southern California.