Pace of Motor Vehicle Sales Looks Promising for Spring : Autos: Detroit’s Big Three are boosting production to meet demand. Consumer confidence is called the key to a big new-car year.

Auto makers today are expected to report a robust 20% gain in car and truck sales for March, but analysts warn that consumers may get cautious and cause a slowdown later this year.

For the time being, however, the outlook is strong, with estimates of March sales running at an annualized rate of 16 million vehicles, including imports.

“March looks pretty awesome,” said analyst Bernard Campbell of DRI-McGraw Hill in Boston. “All signs are that March may be one of the best months of the year, if not the best month of the year.”

Sales in March, 1993, ran at a rate of about 13.3 million units, including imports.

This year, sales of U.S.-built vehicles alone are expected to top that level, with domestic sales in March estimated at about 13.6 million units, up from 13.3 million in February.

Chrysler Corp. has said March was likely to be an all-time record sales month, as it delivered between 12,000 and 13,000 new Neon cars. Chrysler Marketing Vice President Thomas Pappert said industry sales for the year could reach 16 million units.

Analysts say that Chrysler’s estimates may be overly bullish, however, and that 15.5 million units is more likely.

But they agree that sales should remain strong in April and May, the customary spring selling season. “We feel confident that we’ll have selling rates around 16 million for the next couple of months,” said analyst Michael Luckey of the Luckey Consulting Group.

Ford Motor Co. Executive Vice President Ed Hagenlocker said he expects truck sales to set a new record for March.

“The industry was really running very strong in March, and ran very strong in February,” Hagenlocker told reporters at Ford’s Cleveland Engine Plant No. 2. “I would anticipate again the truck industry setting all-time record sales in March.

“The car industry has gotten considerably stronger,” he added.

To meet the demand, Detroit’s Big Three plan to boost second-quarter production 11.6% from the equivalent period last year, to 2.71 million units, according to Ward’s Automotive Reports.

The Detroit trade publication said General Motors Corp. plans to increase its second-quarter production 13.3%, to 1.28 million units. Ford will raise production 6.8%, to 1.0 million units, and Chrysler has scheduled an 18.9% hike to 428,000 units, Ward’s said.

Five European auto makers reported Tuesday that their March sales in the United States rose a collective 26.4% from March, 1993. Bavarian Motor Works (BMW) car sales rose 16.5% to 7,283 units; Volvo’s sales rose 39.6% to 8,804 cars; Saab Automobile sales rose 10.8% to 2,335.

Porsche’s U.S. sales rose 64.4% to 457 units; Land Rover sales fell 8.4% to 336 units.

Automotive analysts said the boom may taper off during the second half of the year, if interest rates continue to climb and consumer confidence falters. “We could see sales slow down a bit,” said Lehman Bros.’ Joseph Phillippi. “The line never goes straight up.”

The stumbling stock market’s effect on consumer confidence is particularly worrisome, since there are millions of relatively new investors in stocks and mutual funds.

Analysts generally said they expect sales to hold in the 15-million-unit range through 1996. The record year for auto sales in the U.S. market was 1986, when auto makers sold 16.3 million vehicles.