Federal regulation of the troubled auto industry is emerging as a probable presidential campaign issue for Jimmy Carter and Ronald Reagan.

The issue isn't on any formal debate agenda, and neither candidate has officially won his party's nomination. But both men are talking about how to rescue domestic manufacturers from slumping sales and employment.

Reagan, going beyond an earlier generalized charge that the industry "is virtually being regulated to death," said last week that there should be "an immediate moratorium on all new federal auto regulations." The moratorium shouldn't be lifted, he said in a statement in Dearborn, Mich., until the effects of such regulations -- particularly on auto workers' jobs -- can be determined.

Carter has rejected such a drastic approach, according to two participants in a May 14 meeting here at which the president, Cabinet officers and White House aides conferred with top officials of General Motors, Ford, Chrysler, American Motors and Volkswagen of America.

The sources said the president, in remarks at the meeting, gave or tried to give the impression that he has an open mind toward proposed standards, as shown by his recent order for the Department of Transportation (DOT) to review them.

At the same time, the sources said, he did nothing to indicate he would endorse a wholesale attack on rules intended to make cars safer, burn less fuel and emit less pollution.

"I don't think there's much chance of the Congress or the public accepting lower environmental, fuel economy and safety standards," one of the sources quoted Carter as saying.

Only American Motors' Gerald Meyers urged a moratorium on more stringent standards. Chrysler's Lee Iacocca, though he shares in the companies' dislike for the regulations, took a different tack.

Iacocca suggested, the sources agreed, that the regulations have nothing to do with the industry's principal problem in the next two years: a shortage of capital for dealers and of credit for car buyers. Carter, in a step to aid the industry, announced after the meeting that the government will try to make available more credit for car buyers.

Once this critical period has passed, the industry should be offering fuel-efficient cars starting with the 1983 models, Iacocca is reported to have said, remarking pointedly to his fellow executives that if the industry isn't ready, "shame on you."

Volkswagen's James McLernon proposed a tax credit for buyers of fuel-efficient cars. He didn't discuss regulations, a reporter was told.

The manufacturers seeking federal aid, critics have long complained, continued to make so-called "gas guzzlers" through the late 1970s of their own choice -- not because federal regulations required them to. Indeed, it was the legislation mandating fuel-economy standards that forced domestic producers to meet foreign competition with a shift to economy cars, the critics say.

DOT Secretary Neil E. Goldschmidt, reacting to an earlier Reagan charge that the administration "is conducting a concerted campaign to cripple the American automobile industry," said Reagan "will have a tough time explaining . . . how fuel-economy standards prevent our industry from competing with the small Japanese and German cars," which must meet the same standards. w

Quoting Goldschmidt in his Dearborn statement, Reagan termed the secretary's response an "incredibly cynical defense of the government-caused pain in our auto industry . . ."

He said the fuel-economy standards "discriminate against American automakers because they may force the industry to devote significant amounts of time, money and manpower to making incremental improvements to meet the arbitrary year-by-year mileage stands, rather than concentrating on making the long-term changes necessary to compete with imports."

Reagan said the government should retain but not go beyond the present standard for 1985 of an average of 27.5 miles per gallon for each maker's fleet. Over industry opposition, the Senate Energy Committee is debating whether to try to raise the requirement to 40 mpg by 1995.

A major focus in both the Reagan statement and the White House meeting was the standard for passive restraints -- air bags or automatic seat belts intended to protect a vehicle occupant without any action on his or her part.

Reagan charged that the requirement discriminates against domestic manufacturers mainly becuase it applies in the 1982 model year only to standard and luxury-sized cars. The standard reaches intermediate and compact cars with the 1983 models, and subcompacts with the 1984 models. In Reagan's words, the standard "won't effect small cars -- and hence foreign imports -- until 1984."