This is the third straight week of declines, according to the government's new survey, although the drop amounts to less than a nickel a gallon in the L.A. area. The average price of self-serve regular is now $4.566 a gallon. Oil, meanwhile, fell almost $4 a barrel today, to $141.37, helped along by a stronger dollar and evidence of slower demand in Europe. When the dollar strengthens, investors around the world become less willing to buy oil. Don't discount profit taking either.