WASHINGTON — A report due out Wednesday is expected to show that inflation remained in check last month, as the weak U.S. economy prevents retailers and manufacturers from raising prices.

The report comes after the Commerce Department said Tuesday that retail sales jumped in August by the largest amount in more than three years. Labor Department data also showed that excluding volatile energy and food costs, core inflation posted a modest 0.2 percent increase, as measured by the Producer Price Index.

Still, economists warn that as long as credit stays tight and jobs remain scarce, Americans probably aren't ready to spend in force again. The Consumer Price Index is forecast to have increased by 0.3 percent in August, after remaining flat in July, according to economists surveyed by Thomson Reuters. Excluding volatile food and energy prices, economists expect only a 0.1 percent rise.

Analysts expect the CPI to fall by 1.7 percent compared with a year ago, mostly due to lower oil and gas prices. That follows a 12-month drop of 2.1 percent in July, the steepest in nearly six decades. Excluding food and energy, prices are forecast to have risen 1.4 percent in the 12 months ending in August.

The retail sales gains for August included a big jump in auto sales, mostly from the government's recently ended Cash for Clunkers program.

Retail sales overall rose by a seasonally adjusted 2.7 percent, the largest gain since 2006, the Commerce Department said.

Economists were cautious.

"We need more data to see if this is sustainable or just noise," Ian Shepherdson, chief U.S. economist at High Frequency Economics, wrote in a research note. "The income and credit constraints on consumers remain intense."

The Fed is expected to report some good news Wednesday when it releases its industrial production report. Economists expect that output at the nation's factories, mines and utilities rose 0.6 percent in August, according to Thomson Reuters.