DETROIT -- Is it a mere stubbing of a giant's toe that has General Motors hobbling? Or is the nation's largest corporation permanently crippled? Either way, GM has been humbled.

For the first time since the 1920s, GM is second to Ford in profits: $2.9 billion on $102 billion in 1986 sales to Ford's $3.3 billion on $62 billion. GM's share of the market has decreased 5 percent in two years. Its factories are operating at 77 percent capacity, against Ford's 115 percent.

The only boast GM retains is that it still runs the largest lemon grove north of Florida: Recalls for Chevrolets, Buicks, Pontiacs, Oldsmobiles or Cadillacs have occurred in every year of this decade. The defects -- in cars, trucks, school buses and transit buses -- have ranged from brakes and steering shafts to fuel pumps and throttle springs.

The General Motors of 1987 appears to be as managerially inept as the GM of the 1960s and '70s when it was losing useless and costly battles against everyone from Ralph Nader to federal regulators. It continues to market cars as if the public has collective amnesia about GM's record of shoddiness. According to the Center for Auto Safety, 25.9 million GM vehicles have been recalled in the past 10 years. The figure is 38 percent of the industry total. As showrooms fill with 1988 models this month, the corporation's ad campaign -- three full-page announcements on one day in one major newspaper alone -- promotes the fantasy that "GM is committed to quality."

The sole customer that might be buying the quality line is the Pentagon, where standards of excellence for weapons are as low as a dragging tailpipe. GM now has $5 billion in military contracts, up from $1.6 billion the previous year and making it the Pentagon's fifth largest contractor.

This latest peril to national security aside, GM's current ad campaign boasts of "major advances in equipment and technology." These include the "Quad 4 engine" that set a testing-ground speed record "of better than 257 mph," exactly what people need in the daily rush-hour traffic crawl. The air bag safety device, the one major advance that means anything for people who look at the statistics and see automobiles as death traps, has been evaded by GM for more than 15 years. By the corporation's own estimates, air bags -- exhaustively tested, inexpensive and reliable -- can save 6,300 lives a year. Others say 9,000.

In 1970, GM promised a voluntary program to put air bags in all cars and trucks by 1975. That was a pledge offered as a trade-off to delay a federal mandatory standard for passive restraints. In 1980, the corporation, seeking another delay, promised that "by 1984 virtually all our cars will be equipped with passive restraints."

None of these promises has been kept. The air bag was sold in some GM cars in the mid-1970s but not promoted. With other carmakers, including Ford, Volvo, BMW, Mercedes and Honda, choosing to be leaders in installing air bags in all or some models, GM is far behind. Its shame doesn't preclude the kind of hollow bragging that is standard equipment on GM statements: "During the 1992 model year, the production of GM driver air-bag-equipped vehicles could approach 3 million units. This would make GM the largest supplier of inflatable restraint systems in the 1990s."

That's from the corporation's 1987 "public interest" report, a phrase it apparently learned from Ralph Nader. If you can't beat them, steal their language.

In an interview last week, a GM vice president portrayed his company as a leader in safety, technology and civic-mindedness. He told of GM safety engineers who are working on crashworthy cars that will offer protection without seat belts or air bags: "That's an enormous technological achievement."

It's also futuristic double talk. This is a company whose leaders opposed lap belts in the 1950s, shoulder harnesses in the 1960s and air bags in the 1970s. Their gift to the public in the '80s is an engine that can hit 257 mph. The company remains unable to deal creatively with its critics. Of Ralph Nader, the GM vice president said: He "has a fundamental distrust of people. He wants to tell the public what it should have. We try to listen and ask the public what it wants."

Presumably, GM has a vault of secret studies in which customers demand lemons, defects and unsafe vehicles. GM's decline in profits and market share is a sign to many that its financial losses are at last catching up to the company's moral losses.