Lila Frazell wasn't looking for a car with a four-cylinder engine when she started shopping at a Chrysler dealership in Albuquerque, N.M., early this year. But the black Sebring midsize sedan on the lot at Quality Jeep-Chrysler had all the options she was looking for, including a two-tone beige-and-tan leather interior.

"I got in the Sebring," the 61-year-old paralegal recalled. "It had everything I wanted, and it had plenty of power."

Frazell ended up buying the car, joining an increasing number of U.S. car shoppers who are picking thriftier small engines in the face of gas prices that continue to hover around $3 per gallon.

The percentage of four-cylinder engines in U.S. vehicles has been rising slightly since 2002, but it still was only 25.4 percent of the U.S. engine mix in 2006, according to data collected by Ward's Automotive Group.

Still, in midsize vehicles where consumers have a choice, the majority has picked four-cylinder engines so far this year in nearly all of the best-selling models made by the top five U.S. auto sellers.

At DaimlerChrysler AG's Chrysler Group, 72 percent of Sebring buyers drove off with four-cylinder engines through May, compared with 53 percent in the previous version of the Sebring, which was phased out last year.

Chrysler, in preparing to launch the new Sebring, looked at government gas price statistics and made last-minute changes in its lineup to offer a four-cylinder engine even in decked-out versions of the vehicle, said Joel Schlader, brand manager for the car.

Four-cylinder engines generally get better gas mileage and pollute less than their larger counterparts, although they often are noisier and don't accelerate as well. In many cases, the sticker price of a four-cylinder car is lower than the V-6 version, sometimes by more than $1,000.

Before the recent spike in gas prices, buyers of midsize cars made by the Detroit Three typically went for more powerful and quieter V-6 engines, while those who bought the popular Toyota Camry and Honda Accord Japanese midsize cars generally bought more four-cylinder engines, Schlader said.

"People thought maybe we were crazy," in putting out more four-cylinder Sebrings, Schlader said. "The demand is clearly there, so if we wouldn't have done that ... I think it's safe to say we might be missing some business."

At Ford Motor Co., where 54 percent of midsize Fusion buyers have bought four-cylinder engines through May, demand for the smaller engines has shifted with gasoline prices since the car was introduced in late 2005, said George Pipas, the company's top sales analyst.

Later this year, when gasoline prices are expected to drop after the peak summer driving season, demand will move back toward six-cylinder engines, Pipas said.

The swings have presented a challenge to Ford's production system, but it has been flexible enough to handle the changes, Pipas said.

General Motors Corp. saw dramatic increases in four-cylinder sales in two of its most popular midsize models, the Pontiac G6 and Chevrolet Malibu, when comparing 2006 statistics to numbers through May of this year.

The increase of around 20 percentage points for each vehicle is partly due to demand and partly because GM was limited in its ability to put four-cylinder engines in the 2006 models, said spokesman John McDonald. He said he did not know exactly what caused the limits.

Four-cylinder engine purchases dropped on Toyota Motor Corp.'s Camry from 75 percent in 2006 to 67 percent through May 2007, mainly because the company added a hybrid gasoline-electric version in the 2007 model year, said spokesman Mike Michels.

For Toyota and other automakers, computerized six-speed transmissions and other technology advancements have made V-6 engines almost as efficient as fours, according to industry analysts.

On the Camry, the nation's top-selling car, the four-cylinder engine with a manual transmission gets an estimated 34 miles per gallon on the highway, while the six, with a six-speed automatic, can get 31.

Rebecca Lindland, an auto analyst at Global Insight, an economic research and consulting company, said automakers have improved four-cylinder engines in recent years, making them more powerful and quieter.

Many U.S. car buyers, though, still think the smaller engines are noisy and don't have enough power, so manufacturers must overcome an image problem, she said.

"You're looking at a consumer base that has always said `Oh, four-cylinders. That's too small,'" she said. "The long-term situation that we find ourselves in with high gas prices does force a change in consumer behavior and consumer open-mindedness."

Chrysler's four, made at a new factory in Dundee, about 40 miles southwest of Detroit, is relatively large at 2.4 liters and has 23 more horsepower (173) than its predecessor. Its power is close to that of many small V-6 engines, and it gets an estimated 32 mpg on the highway.

Chris Nathe, sales manager of the dealership where Frazell bought her car, said he was skeptical when he saw Chrysler shipping feature-loaded Sebrings with the smaller engines.

"People buying American cars typically like more horsepower and more torque," he said.

But after test-driving them, customers have liked and purchased cars with the smaller engines, Nathe said.

"They feel the engine has plenty of power, and they like the fuel economy," he said.

Although Frazell didn't buy her car to get better fuel economy, she said she's happy she has the smaller engine for her 20-mile one-way commute on city streets, where she gets around 23 mpg.