Even when he's getting his Saturday-morning espresso at Starbucks, Bill Ford Jr. can't escape the pressures of being Detroit's best-known environmentalist. On his days off lately, the automotive scion and CEO of Ford Motor Co. has been buttonholed by greenies demanding to know why he hasn't come out with cars that run on air. That's right, air. A tiny company in Luxembourg claims to have invented a car that powers the pistons with compressed air (it promises to put them on sale next year, but the company has failed to deliver before). Since that "breakthrough" news hit the morning shows in October, Bill Ford--the self-described "environmental industrialist"--has been inundated by people accusing him of hiding magical air cars in his company's garages. "People think we have these things squirreled away somewhere and that we're artificially suppressing them," he says. "You know how crazy that is?"

Bill Ford has learned the hard way that it isn't easy being green. When he became chairman of his family's auto empire in 1999, he boldly declared a "clean revolution," in which--he said in a sly paraphrase of his great-grandfather--"customers can have any vehicle they want, as long as it is green." He broke ranks with Detroit by admitting that cars cause global warming and that SUVs can be a menace on the road. But then the earth fell in on Ford Motor Co., and Bill Ford had to defer his grand ambitions. By the time he ousted Jac Nasser in 2001 and took the wheel as CEO, the automaker was spinning out of control from the Firestone debacle and losing billions. Now, though, he has finally nudged the family firm back into the black and Ford, 47, is ready to revive his clean revolution. After all, his long-awaited gas-electric-hybrid Escape SUV is finally on the road--just as drivers are looking for more fuel-efficient wheels with gas hovering around $2 a gallon. Plus, he's cranked up his new ecofriendly factory, with the world's largest "living roof" blanketed in flowering ground cover. He's even convened a panel of young execs to tackle the thorny issue of how Ford can clean up its cars to combat global warming. The boyish optimism he once displayed about saving the planet has now been replaced by a world-weary determination to re-establish Ford's green credibility--and his own. "I have to look in the mirror every day," he tells NEWSWEEK. "And to me, this commitment is not something new. It's not some PR person's dream. In fact, it's probably a PR person's nightmare."

And it's one he can't seem to wake up from. This week, the Union of Concerned Scientists says, it will criticize Ford for having the auto industry's worst gas mileage, while lauding Honda and Toyota for making the most fuel-efficient cars. Last week the Rainforest Action Network ran an open letter to Bill Ford in The New York Times featuring a flag-draped coffin and the headline gas guzzling is un-american. "Mr. Ford burned his bridge, and it's going to take a long time for him to rebuild it," says Russell Long, head of the Bluewater Network, which ran an ad that caricatured Bill Ford as Pinocchio for going back on a promise to boost the company's SUV gas mileage by 25 percent. Instead, the EPA says Ford's SUV fuel economy has improved only 5.6 percent since that pledge was made in 2000. In hindsight that promise was overly optimistic, Ford says, and the company's financial crisis stalled progress on environmental efforts. "My passion for the environment hasn't waned one bit over the years," he says. "It's just that events overtook me when I became CEO, and the fires were raging everywhere." Now he won't publicly commit to any hard targets, even refusing to confirm leaks from his own execs that Ford is aiming to cut in half the global-warming gases coming from its cars by 2030, which will require an 80 percent boost in gas mileage. "These are the kind of issues I'm driving personally," he says. "But I won't speak externally to numbers because a cynic would say, 'Well, it's easy to make a promise that far in the future'." He's right, but even his allies want something tangible on how he's cleaning up his cars in the next five years--not in a quarter century. "We're rooting for him," says environmental shareholder activist Mindy Lubber. "But he's got to act sooner."

Bill Ford may tussle with the tree huggers now, but he can still sound as if he just came from a Greenpeace rally. While meeting in his earth-friendly office--built entirely from renewable materials like recycled-newspaper ceiling tiles--he easily slips into enviro-geek-speak about how to extract hydrogen from a landfill. He enthuses about hydrogen cars his engineers are working on and how the hydrogen economy will replace fossil fuels in his lifetime--"The real issue is when renewables are economically viable." But when asked about how his old friends have turned on him, he stiffens. "Do I like it? No," he says. "But is it going to slow me down at all? No."

The biggest skeptics Bill Ford has faced, though, have been in his own ranks. When Ford was losing money, he says he had to fight off high-level attempts to euthanize the hybrid Escape and his $2 billion environmentally friendly factory. "Many of my executives said, 'Hey, we've got to kill this. This is something we just can't afford'," recalls Ford. "My rejoinder was: 'This is something we simply can't afford not to do'." Without his protection both projects would have died, says Debbie Zemke, Ford's closest environmental adviser until she retired in August in frustration over the slow pace of progress. She says there are still old-school execs at Ford who view environmentalists as foes, despite the CEO's leanings. Zemke says top marketing execs this summer refused the Sierra Club's offer to tour the country promoting the Escape. They felt burned by the Sierra Club's past criticism. "I was told, 'We can't trust them'," recalls Zemke. Toyota, by contrast, includes a Sierra Club official in its dealer-training film for its Prius hybrid.

The hostility toward Bill Ford's environmental agenda was once much worse. Just ask Vance Zanardelli, chief engineer of developing cars that run on hydrogen instead of gasoline. Nearly four years ago Ford ran into Zanardelli and his small band of engineers as they all waded into the Rouge River in Dearborn on an environmental cleanup. They pitched Bill Ford on fueling regular engines with hydrogen now in order to pave the way for the fuel-cell cars. Ford gushed: "Where have you guys been hiding this?" But back at the lab, when Zanardelli bragged that Bill Ford backed his project, a company VP scoffed: "That's the dumbest idea I've ever heard." Now, though, the CEO's support has boosted Zanardelli's budget tenfold and he's preparing to roll out a fleet of hydrogen airport vans. "It's no longer just Bill and me," says Zanardelli.

While Bill Ford has struggled to win over his own workers, Toyota has captured the environmental high ground. Building on the Prius's success, Toyota will launch as many as four new hybrids next year. Ford's next hybrid, a Mercury version of the Escape, won't arrive until 2006. Bill Ford clearly doesn't like playing catch-up. "I can't control what people think of Toyota," he says. "All I can control is what they think of us. And that's what I'm working really hard to get right." He knows it will take more than one hybrid and one clean factory. And he insists he won't veer off the garden path again. "Ultimately, if people judge this is the wrong road to be on, then I'm not the guy to do the job," he says. "Because I'm not changing." Don't expect Bill Ford to be job hunting. At Ford, the guy whose name is on the building ultimately wins all arguments.