Washington — Japanese cars are selling briskly in the United States. American carmakers are holding their breaths. And the Japanese are struggling to find consensus on what to do next.
That is where the debate now stands concerning the number of Japanese cars to be offered to American customers this year and in the years just ahead.
"Our sales over the last three months," says Rod Ritter of Ritter Datsun in White Plains, Md., "are running well ahead of the same period of last year."
Why? Are customers afraid that prices will be higher if imports are restricted?
"Perhaps a few," says Mr. Ritter. "But, in the main, they say they're looking for the quality of the import."
Meanwhile, to stave off congressional action that might slap new tariffs or quotas on Japanese cars, Japanese leaders are pondering what to do.
"Voluntary" is the key word. Tokyo seeks a formula preserving the free-trade stance of the Japanese and the Reagan administration, while still reducing the number of shipments below the 1.9 million cars of last year.
At the same time, the solution must avoid breaking antitrust laws in the US.
The Japanese, according to a top US official close to the problem, have two options:
* The government can invoke the Japanese Export-Import Control Act, which allows Japanese industries to form cartels for export purposes.
This device was used when Japan agreed to cut back its color TV shipments to the US. An American court ruled that the action did not violate antitrust laws, essentially because it was "permissive."
That is, the government encourages -- but does not order -- Japanese firms to form a cartel to curtail exports.
"But," said the Washington official, "there must be a consensus [between government and the car industry] and so far there is none."
Japanese automakers, fiercely competitive at home and abroad, have not yet agreed to restrict their US sales.
* The Japanese government has a fallback possibility --stiffer law mandating export restrictions.
Under this solution, the government would order Honda, Toyota, Nissan, and the others to cut back their exports by a specified amount.
But American importers of Japanese vehicles and a large network of dealers might challenge this law on antitrust grounds in US courts, where the outcome is regarded as uncertain.
Meanwhile, the Reagan administration sits tight, having responded to US industry pleas for protection by pledging to reduce the costly burden of federal regulations on US automakers.
President Reagan opposes quota or tariff restrictions on imports, emanating either from Congress or from his own administration.
One reason why Japanese automakers are reluctant to cut back shipments is their major investment in large dealer networks, able to offer service to customers anywhere in the US.
Japanese firms want to pump enough vehicles into that dealership chain to keep its members viable, experts say.
Meanwhile, many American dealers who handle Detroit's products are adding Japanese franchises to their lines. Conversely, a number of dealers in Japanese cars are adding domestic car lines to protect themselves against possible import curbs on Japanese models.
In other trade fields, US officials continue to press the Japanese to open their markets more fully to American goods -- especially farm products.
Meat, rice, citrus fruits, tobacco, and leather goods, American officials say , run up against Japanese trade barriers that the US calls unfair.
"Beyond this," said a senior US official, "the Japanese make it very hard for Americans to get in at an early stage of [product] development."
A lot of US investment money and know-how, he claims, has been shut out of Japan as new products were brought along, "giving the Japanese -- in effect -- a closed market in which to develop eco nomies of scale."