Just when they thought they were catching up with Toyota Motor Corp.'s pacesetting lean production methods, the world's other automakers face a new threat: Toyota is set to become still leaner.

Already the envy of everyone else as the lowest-cost producer of high quality vehicles, Toyota is waging yet another war on waste.

Spurred on by the persistently strong yen, which has forced price increases repeatedly in its major export markets, Toyota already has slashed costs $2.2 billion in the last 18 months, including $700 million in 1994's second half

All of that came before the U.S. in May slapped a 100% tariff on Toyota's five Lexus luxury models, which range from $31,500 to $51,200, and eight other Japanese luxury marques. The tariff does not become effective until late this month, if then; nearly everyone involved thinks Japan and the U.S. will strike a compromise.

U.S. International Trade Commissioner Mickey Kantor ordered the punitive tax after negotiations over the 1994 $37-billion U.S. automotive trade deficit broke down The U.S. wants freer access to Japan's car market and is pressuring the Japanese to buy more U.S.-made automotive components.

That's an old, old song - U.S. administrations have been singing it for nearly 20 years - aimed at reversing the automotive trade deficit. First it triggered "voluntary" quotas on Japanese vehicle imports. Then came a wave of Japanese "transplant" production facilities in North America, followed by a series of expansions.

In May, for example, Toyota announced a $443-million plan to raise production in Canada from 85,000 to 200,000 yearly by 1997, amid speculation it may build at least one Lexus model there - possibly the front-drive ES300. The world's third largest automaker at the same time revealed it will add a newly designed front-drive minivan at its Georgetown, KY, assembly plant in 1997. Toyota's total North American capacity will hit 900,000 annually by 1998.

The timing of these announcements, coming during the trade talks, is not coincidental. Toyota and the other Japanese automakers have made similar moves to head off U.S. negotiators.

Reflecting in part their growing North American presence, the Japanese have raised purchases of U.S. components from $2.49 billion in 1986 to $19 billion last year, which includes a sizable amount from Japanese transplant partsmakers. Those numbers also include, Toyota emphasizes, purchases from the U.S. Big Three automakers' components operations.

During that same period, Toyota's purchasing outside Japan - combined with imports to its home market from abroad such as the 67,000 Camrys shipped from Georgetown in 1994 - grew to $9.7 billion from $2.2 billion, Executive Vice President-Production Toshimi Onishi tells reporters at a Detroit gathering. During 1994, he adds, Toyota's purchases from North American suppliers reached $5.2 billion, and the target by 1996 is $6 billion annually.

"We are beginning to localize models for major markets," he says.

Greater efficiency and affordability are keystones of that strategy. But Toyota is not stopping there. "We are evaluating the design and materials of every item we use in our cars" and "identifying opportunities to make changes that lower costs without affecting quality and performance," says Mr. Onishi.

Sounding like his American counterparts, Mr. Onishi says Toyota will drive for more common parts shared over several models to retain diversity while shaving costs. The new minivan, for example, will utilize Camry mechanicals. "We've had 100 types of steering wheels," he says. "Maybe the customer doesn't need 100; maybe 70 would be enough."

Toyota's new attack on fat "applies to all aspects of our business," says Mr. Onishi, who admits that "we got a little carried away with automation and big equipment a few years ago." Toyota since has "discovered that we can do some work better with semi-automated equipment and smaller equipment."

Armed with a $28-million cash stash, what's the urgency of getting still leaner? "Our funds haven't decreased, but interest rates are down, so this is having an impact," he says. "All of these things are spurring us on to become leaner and leaner."

Which may spell bad news for Toyota's competitors, including at least a few based in its home market.