WASHINGTON (MarketWatch) — The economy has been jolted by a number of speed bumps since the U.S. exited recession five years ago, and now another hurdle is looming.

Even as U.S. growth accelerates, the rest of the world is slowing down. Continental Europe and Japan might be on the verge of another recession and China’s economy has clicked down to a lower gear.

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What happens around the world is no small matter to American consumers and businesses since trade represents a greater share of the economy than ever before. That’s why worries about the global outlook spooked U.S. stock markets last week.

The shift in economic fortunes has already triggered a sharp uptick in the value of the U.S. dollar DXY, +0.41% and made American goods more expensive on global markets. Slower growth abroad could dampen U.S. exports, cause businesses to put off new investment or even hire fewer people.

“Europe seems to be back on the ropes,” said Gustavo Reis, an economist at Bank of America/Merrill Lynch. And “global growth seems stuck in a rut.”

The news is not all bad, though. Slower global growth, combined with soaring U.S. oil production, has knocked the price of crude oil down to its lowest level in two years. And prices are expected to go even lower.

The result: Americans will pay less to fill up at the gas station, giving them more money to save or spend on other things.

“The drop in gasoline prices arguably boosts growth as much as the strengthening dollar weakens it,” said Neil Dutta, head of economics at Renaissance Macro Research.

The weaker global economy has also eased inflationary pressure, especially good news for anyone who wants to buy a car or a house. A 30-year mortgage, for example, has fallen back toward 4% after hovering around 4.5% for much of the year.

What’s less clear is whether the effects of these trends will show up in a pair of key economic reports this week on retail sales and new home-construction in September. Retail sales are forecast to fall — mainly because of a dip in auto purchases — while housing starts are projected to rise incrementally.

Sales at retailers have been soft for most of the year despite improved U.S. growth and the fastest pace of job creation in more than a decade. Higher food and gasoline costs earlier in the year was one impediment, but sluggish wage growth is a more persistent straitjacket. Annual wages aren’t rising much faster than the rate of inflation.

There are some signs wages might be starting to pick up, and many economists believe consumers will increase spending in the near future. More people are working, gas prices are falling and household debt levels are the lowest in years.

But previous forecasts of higher spending haven’t materialized and the behavior of consumers has been anything but predictable.

Consider home sales. Despite exceedingly low interest rates and rising family formation, Americans are not buying nearly as many houses as industry experts expected give the overall improvement of the U.S. economy.

Maybe that will soon change, but don’t count on it if weaker global growth continues to batter the U.S. stock market and undermine the confidence of investors, consumers and businesses.

“We have been in such a slow steady recovery for so long. it’s become hard to envision anything else,” said Lawrence Creatura, a value-fund manager at Federated Investors. “You can’t deny the economy is getting better, but we’ve seen little to suggest it will trump the modest growth we’ve been experiencing.”