Fuel prices lift US inflation in September US inflation rose in September for a second consecutive month, as a jump in energy costs overshadowed much smaller gains in other goods and services The headline consumer price index rose 0.6 per cent last month, a repeat of August which was the largest rise since June 2009 and the first uptick in five months. This was the largest back-to-back gain in four years. The data from the labour department came in higher than analysts" expectations of a 0.5 per cent increase. The core CPI - which excludes volatile energy and food prices - increased 0.1 per cent for a third month in a row, slightly below consensus forecasts of a 0.2 per cent rise. In the 12 months to September, core prices rose by 2 per cent compared with a 1.9 per cent year-on-year gain in August. The US Federal Reserve has said it is not worried yet about a spike in inflation and is more focused on the other half of its dual mandate of maximum employment. The cost of living was boosted by a 7 per cent jump in petrol prices, following a 9 per cent surge in August, which was the biggest one-month increase since November 2009. A gallon of regular fuel cost roughly $3.83 in September, the highest level since April and up 13 cents from August, according to AAA, the US motoring group. The energy index overall jumped a monthly 4.5 per cent after increasing 5.6 per cent in August. Jonathan Basile, director of economics at Credit Suisse, said in spite of the jump in fuel costs, consumers continued to make purchases. "As yesterday's retail sales report indicated, consumers were undeterred in August and September and ramped up spending in both months," he said. The increase in food prices eased to 0.1 per cent after rising 0.2 per cent in August. Excluding energy and food, the cost of housing, medical care, apparel and airline fares rose, while prices for used cars and trucks, new vehicles, personal care items and household furnishings declined. The September CPI report is used for the calculation of the 2013 Social Security cost of living adjustment, which came in at 1.7 per cent, about half last year's 3.6 per cent increase.