Diesel rose 5.6 cents to $4.15 a gallon, its highest national average pump price in more than four years, while gasoline fell for the third time in four weeks. The diesel increase leaves it 34.9 cents higher than the same week last year. Gasoline is 34.3 cents over a year ago. Prior to last week’s 1.5-cent gain, diesel had dropped for two straight weeks. Before that it rose almost 49 cents in 11 consecutive increases. Gasoline has dropped a cumulative 5.9 cents in the past four weeks — 10.5 cents of declines in three downturns, along with a 4.6-cent increase last week. Prior to that, the motor fuel rose 52.2 cents in 11 increases.