DETROIT — A sense of urgency enveloped three Republican presidential campaigns yesterday as Mitt Romney, John McCain and Mike Huckabee reached out to as many voters as possible to ensure a victory in Tuesday's primary.

Romney, a Michigan native and former governor of Massachusetts, added several events to his campaign schedule, including a stop outside a General Motors plant in Ypsilanti, where another layoff was announced last week.

Arizona senator McCain continued to emphasize his reputation as a straight talker, even if some of his messages are difficult truths to hear.

And Huckabee, the former Arkansas governor, spent his last day in the state burnishing his everyman image with a rally in Grand Rapids, followed by an impromptu gig with a jazz band at the Amway Grand Hotel.

All three candidates talked about Michigan's ailing economy and a need for fundamental changes in Washington.

In an interview with the Detroit Free Press, Romney said he will announce detailed plans on how to help the domestic auto industry comply with new, stricter, fuel-efficiency standards during a speech tomorrow at the Detroit Economic Club.

"CAFE placed a huge burden on the domestic auto industry, and we're about to impose new CAFE standards," he said of the corporate average fuel economy. "We have to find new ways to lighten the load."

The speech is crucial for Romney, who is desperate for a win after finishing second in Iowa and New Hampshire.

Both Romney and McCain spoke at the Americans for Prosperity summit in Livonia yesterday afternoon. The group, which favors limited government, less regulation and fewer taxes, gave an enthusiastic response to Romney.

"Anyone earning $200,000 or less would have a new tax rate on their savings," he said. "And that tax rate is zero."

McCain's reception was a bit chillier, especially when he talked about immigration. He supports a more secure border, but he also wants to initiate a system that does not kick all illegal immigrants out of the country.

The topic set off a rare, raucous moment on the campaign trail as McCain got catcalls from several angry critics in the packed auditorium.

One yelled that the tax burden of supporting illegal immigrants is too high. Another shouted, "What about your culture and language?"

McCain refused to bend on his position that after deporting illegal immigrants who have committed crimes and creating a temporary worker program, a system needs to be developed that doesn't deport the rest — as many as 10 million people — wholesale.

There might be a soldier in Iraq whose mother is here illegally. "I won't deport her," he said to one person in the audience. "You can."

He also spent the day fending off attacks from Romney about comments McCain has made that some jobs lost from the auto industry would probably never return.

McCain said he was being realistic. And he said Michigan has the productivity, workforce and technological know-how to create a new economy.

"The answer is not to create false hopes that we can bring back lost jobs, but that we can create new ones," he said.