Former Michigan Gov. William Milliken has announced his endorsement for John McCain, less than two days before Michigan's primary and just hours ahead of a major economic address was to be delivered by McCain rival Mitt Romney at the Detroit Economic Club.

Milliken endorsed McCain in 2000, when the Arizona senator defeated eventual nominee George W. Bush by more than 100,000 votes in the Michigan Republican primary. Milliken served as lieutenant governor under Gov. George Romney, Romney's father, from 1963-1969. He was then elected governor and held the post until 1982, becoming the longest serving governor in the state. 

"I have long admired Senator McCain for his straight talk and service to the country," Milliken said in an announcement released late Sunday by McCain's campaign. "There's a real sense of integrity in the firm positions he takes, even though they are not always popular. I don't agree with him on all issues, but I like his well-earned reputation of saying what he means, and meaning what he says."

Romney met with Milliken after a rally last year in hopes of gaining his support, but Milliken's decision to back McCain does not come as a surprise to either side, as he is known for holding more moderate positions than Romney.

The endorsement comes at a good time for McCain as Romney, a Michigan native, takes the lead in the state. A RealClearPolitics average of Michigan polls puts Romney at 27 percent, McCain at 26.3. Mike Huckabee has 15.9 percent, Ron Paul has 6.6 percent, Rudy Giuliani has 5.7 percent and Fred Thompson has 5.4 percent in the polling averages. 

But Romney is not curtailed by the endorsement, and is trying to cultivate a relationship with voters from the state that is his birthplace by suggesting he uniquely understands Michigan's economic woes.

Sunday: Mitt Romney addresses reporters outside the

General Motors plant in Ypsilanit, Mich. (AP Photo)

Speaking Sunday in a preview of his economic address, Romney enjoyed a crowd of 350 excited voters who interrupted his speech several times and gave a standing ovation at the end.

Romney said his goal is to make sure the U.S. invests money in future technology, automotive technology, materials technology and energy research. He also took a stab at McCain, without mentioning his name, by saying Washington isn't doing enough to help Michigan.

"I've watched with some dismay as I've watched Michigan have a tougher and tougher time the last 10 years as Michigan has gone through a one-state recession. I don't understand it. I've watched Washington and that's all they seem to be doing is watching. Why aren't they doing something? Why is it that Washington throws anvils, if you will, on the automotive industry and on Michigan and then stands by and sees whether Michigan and the automotive industry can swim with an anvil around it's neck?" Romney said, emphasizing his outsider status while promoting a can-do, optimistic attitude that he says his opponents lack. 

"There are some people in Washington who look at Michigan and they say, 'Boy it's really sad. I'm aware of what's going on there. but, those jobs are lost forever. And I guess my question is which jobs are lost forever?" Romney asked, referencing a comment made by McCain in a debate last week. 

Campaigning around the Detroit area Sunday, McCain said Michigan can be a worldwide leader in green technology, like hybrid or battery-powered cars. He said Michigan has the technical and academic base to make that happen.

On a possible recession, McCain said he doesn’t know if the U.S. is in a recession -- economists are divided on that.  But he repeated what he's said on the issue over the past few days, calling on government to stop the growth in spending, cut pork projects, restore confidence to markets and make permanent tax cuts he originally opposed.

McCain's campaign said the candidate was pleased with the crowd turnout at a town hall meeting and two rallies. Each event was packed with crowds well over 500-strong, sometimes double or triple the expected size. He said he does not know what the outcome will be in Tuesday's primary, but he thinks it will be close.

Part of his good mood Sunday could be attributed to several endorsements in various newspapers, including three in Florida, one in South Carolina and several others in smaller Michigan papers. McCain has taken the lead in national polls.

FOX News' Malini Bawa and Shushannah Walshe contributed to this report.