DETROIT — Passenger car sales plummeted again in March, dragging U.S. auto sales to their third straight monthly decline, a strong indication that years of sales growth have come to an end.

Sales for the month fell 1.6 percent to just over 1.55 million vehicles, surprising analysts who expected a small increase.

For now, anyway, the auto industry isn’t worried. It’s making solid money selling reams of SUVs and trucks to consumers who are loading up on expensive features. But some analysts see large inventories of cars as a looming problem. Car sales were down almost 11 percent, while truck and SUV sales rose 5.2 percent, according to Autodata Corp.

“Trucks and SUVs, although they did well, it’s still hard to make up the lack of car sales,” said Jessica Caldwell, executive director of industry analysis for the Edmunds.com car-buying website. “You can’t have the other side of the industry completely not performing well.”

Hyundai suffered the biggest decline at 8 percent, followed by Ford at 7.5 percent, as popular car models such as the Sonata and Fusion suffered big decreases. Fiat Chrysler sales tumbled 5 percent, Toyota fell 2 percent and Honda just under 1 percent. But Nissan sales rose over 3 percent, Volkswagen’s gained about 3 percent and GM posted a hike of just under 2 percent, all helped by SUV sales.

Drawing in buyers required a lot of cash, low-interest loans and other incentives, however. Dealer stocks are growing because cars and trucks aren’t moving off the lots as fast as they did in the past.

Caldwell predicts sales will drop to 17.2 million, down from last year’s record of 17.55 million.