WASHINGTON — The economy sprinted ahead at its fastest pace in four years during the summer, although it is expected to limp through the final three months of this year as the housing and credit debacles weigh on individuals and businesses alike.

WASHINGTON — The economy sprinted ahead at its fastest pace in four years during the summer, although it is expected to limp through the final three months of this year as the housing and credit debacles weigh on individuals and businesses alike.

The Commerce Department reported Thursday that gross domestic product grew at a 4.9 percent pace in the July-to-September quarter, unchanged from an estimate made a month ago. The performance was especially impressive given that the housing market plunged deeper into despair. Builders slashed spending on housing projects in the third quarter at an annualized rate of 20.5 percent, the most in 16 years.

The economy's growth in October through December is expected to have slowed to a pace of just 1.5 percent or less. Gross domestic product measures the value of all goods and services produced within the United States.

The big worry is that individuals will cut back on their spending and throw the economy into a recession. Former Federal Reserve Chairman Alan Greenspan and others say the odds of that happening have grown this year. Greenspan recently warned that the economy is "getting close to stall speed."

To rescue the economy, Fed Chairman Ben Bernanke and his colleagues have sliced a key interest rate three times this year; those moves dropped that key rate down to 4.25 percent, a two-year low. Still, Bernanke has been criticized for not moving more quickly and aggressively to deal with the problems.

The collapse of the once high flying housing market, a mortgage meltdown and a painful credit crunch, have propelled home foreclosures to record numbers. The problems have forced banks and other financial companies to rack up multibillion-dollar losses, have unnerved Wall Street and have the Bush administration and the Democrat-controlled Congress accusing each other of not doing enough to stem the crisis and scrambling for solutions to curb the fallout.

Credit problems have made it harder for people to get financing to buy a home, aggravating the housing slump. The inventory of unsold homes continues to pile up, forcing builders to cut back even deeper on construction projects. Home foreclosures and late payments are expected to get worse. The troubles in housing are expected to drag on well into next year, acting as a weight on national economic activity.