Car buyers, alarmed by high gas prices, may be starting to reverse a three-year trend of choosing horsepower over fuel economy, according to USA Today. Sales of vehicles powered by four-cylinder engines rose in February to 32.8 percent of the market. In December, their market share stood at 27.8 percent, USA Today said. During the same period, sales of brawny eight-cylinder vehicles fell to 21.4 percent from 25.9 percent, according to the newspaper. The move back to more fuel-efficient four-cylinder engines in the first two months of this year coincides with an increase in gasoline prices, USA Today pointed out. The nationwide average for a gallon of unleaded regular has slipped to $1.687, AAA reported March 25, a retreat from the record average of $1.722 on March 18. Oil prices, though, remain volatile because of uncertainties about the war in Iraq and disruptions in supplies from Nigeria, USA Today said. If crude oil prices zoom, gas prices are likely to follow, putting even more emphasis on fuel economy concerns, according to USA Today.