The U.S. economy more than doubled its pace of growth in the third quarter, as real gross domestic product surged by 2.5 percent from July to September, compared to 1.3 percent in the second quarter. However, analysts acknowledged the data from the Bureau of Economic Analysis is preliminary and may shift in November's official report. Even so, a hike in consumer spending appears to have driven the uptick, particularly as automotive sales and financing picked up. Personal consumption grew at an annual rate of 2.4 percent, compared to a mere 0.7 percent. Price indexes and residential investments also showed improvements. What's more, automotive sales appear to have driven the spike in consumer sales, providing relief for both Detroit manufacturers and resellers. Some analysts worry that the increase will only be temporary, as continued woes in the housing and labor markets continue to mire wider economic growth. "Continued woes in the housing market are overshadowed by consumer concern over the anemic labor market," said Kathy Bostjancic, director for macroeconomic analysis at the Conference Board. "Sustained economic growth above 2.0 percent is simply unlikely."