Diesel fell for the third straight week, dipping 1.2 cents to $4.073 a gallon, and gasoline fell for a fourth week. Gasoline dropped 4 cents to $3.83 a gallon. Diesel’s fourth decline in five weeks left it 5.1 cents below the same week a year ago. Last week was the first time diesel fuel was below its year-ago level since Nov. 16, 2009. The $4.148 national average price three weeks ago was the highest since it was $4.208 on Aug. 18, 2008. Gasoline is now 13.3 cents below the same price last year. Before its recent declines, gas gained a cumulative 71.2 cents in 14 gains in 15 weeks from late December through early April.