The U.S. recovery is hobbled by an economic divide that separates Americans not by income or wealth but by their access to credit.

The housing bust left behind millions of people with credit records damaged by plunging home prices, lost jobs, past overspending or bad luck. Many are now walled off from the low interest rates engineered by the Federal Reserve to spur the economy and remedy the aftereffects of the borrowing boom.

Millions with good credit, meanwhile, are taking advantage of the easy money, a windfall in many cases for people who don't especially need it.

Last year, nearly 90% of all new mortgages originated went to households with high credit scores; before the financial crisis, it was about half, according to Moody's Analytics and Equifax Inc., a credit monitoring service.

Shrunken access among credit have-nots is triggering more than personal plight. It has weakened the influence of the Fed-one of the best hopes for spurring stronger economic growth-and raised doubts within the central bank about whether it is doing much to reduce unemployment.

The debate is especially important now. Fed officials are weighing new steps at their policy meetings Tuesday and Wednesday, following a period of disappointing jobs growth and financial turbulence in Europe.

The credit divide factors into their thinking. Fed officials have been frustrated in the past year that low interest rate policies haven't reached enough Americans to spur stronger growth, the way economics textbooks say low rates should.

By reducing interest rates-the cost of credit-the Fed encourages household spending, business investment and hiring, in addition to reducing the burden of past debts.

But the economy hasn't been working according to script.

After surviving a crisis caused partly by loose lending, banks remain reluctant to extend credit to households with even a hint of financial problems. Fannie Mae and Freddie Mac, the two government-backed mortgage finance firms, tightened their own standards after the crisis. Banks worry Fannie and Freddie will return any troubled mortgages.

Interest rates are now falling more for people with good credit than those with poor credit. Rates on a 30-year mortgage for households with high credit scores of 750 using Fair Isaac, or FICO, ratings, have fallen from 4.44% to 3.53% in the past year, according to the website Loansifter.com. For households with low credit scores of 650, they have moved from 4.82% to 4.04%.

The central bank has said it planned to keep short-term interest rates near zero through 2014. It also has purchased more than $2.7 trillion-worth of government and mortgage bonds to reduce long-term interest rates in less conventional fashion.

The Fed could decide to buy more bonds, or shift its portfolio toward longer-term bonds or mortgage debt to help bring down long-term interest rates. Fed chairman Ben Bernanke said in early June that all options were on the table but was noncommittal about whether he would act.

Some officials worry about the effect of the credit divide. 'I've taken a position of some skepticism, at least under the current conditions, that more policy action would make that much of a difference,' Dennis Lockhart, president of the Federal Reserve Bank of Atlanta, said in a May interview.

Mr. Lockhart has since wavered. He said in a speech earlier this month that he would consider more action if the outlook worsened, then later added he wasn't yet 'quite convinced' that the Fed should do more.

Chris Hordan, who emerged from the financial crisis financially unscathed, is one of the beneficiaries of Fed policies.

With a good income and pristine credit, he has refinanced the $417,000 mortgage on his home in Hermosa Beach, Calif. three times in 17 months, shaving his monthly payments by $390. Multiply the fruit of cheap credit across millions of households-with healthy portions of interest savings spent on goods and services-and the U.S. should be recovering more quickly, according to textbook economics.

But Mr. Hordan doesn't need the money to buy things. His electronic test equipment business has annual revenues of roughly $1 million and he could easily pay off his mortgage with savings, he said. But why bother? Borrowed money is cheap-his mortgage rate is 3.875%-and there are tax benefits for paying mortgage interest. Instead of retiring his mortgage, he is investing the money.

'If you don't need the money, you can get it all day long,' he said. 'Thank you, Ben Bernanke.'

One problem is that financially secure households are less likely than lower-income households to spend their interest rate savings. Wealthier households are more likely to save or invest a windfall because they can already consume as much as they want, according to standard economic theory and research.

Mr. Hordan, for example, is spending his mortgage savings on such investments as gold, emerging markets, U.S. stocks and European banks.

In previous downturns, the lowered interest rates triggered broad waves of mortgage refinancing and new borrowing. The spending that resulted helped power the recoveries.

This time around, many would-be borrowers with lower incomes or blemished credit histories are finding it difficult and more costly, or sometimes impossible, to refinance their mortgages or get new loans.

Giuliana Bernales, a 33-year-old bank analyst in Miami, Fl., bought her Miami condominium two years ago. She lost her job eight months later and made late mortgage payments.

Ms. Bernales said her new job pays roughly $45,000 per year. But she can't refinance her $152,000 mortgage, which is backed by the Federal Housing Administration, because her credit score has fallen, along with her home's value. If she could lower her 5.5% mortgage rate to the current 4% or less, she would save $200 a month.

'For me, that would be a lot of help,' she said. 'They told me I need a year at least of on-time payments.' She recently submitted a new application.

The American credit divide doesn't always distinguish between rich and poor. Bill Hall, a 52-year-old Seattle firefighter, has a six-figure income. He bought his home in Cle Elum, Wash., a Seattle suburb, just as the property boom was about to fizzle in 2007. He paid $320,000, borrowing all of it. The home would now fetch less than $200,000. He said refinancing, even if possible, wouldn't be worthwhile because he would still owe far more than his house was worth.

Mr. Hall suffered a second setback in 2009: a bladder cancer diagnosis that kept him out of work for months. The cancer is in remission but his financial status remains impaired. After a lifetime of timely payments, he said, he stopped paying his mortgage last November, though he remains living at the house. His credit score fell from near 800 into the 600s, from solid to sketchy.

A decade ago, he borrowed against his home to buy cars, boats, motorcycles. 'My whole adult life,' he said, 'I was encouraged to be a good consumer.' Now, he plans to live without debt while he repairs his credit score.

Nationally, there are signs the credit gap is narrowing. Broad refinancing activity has picked up and housing markets have started to improve. Credit has started flowing more freely to low-credit-score households in the auto-lending market.

In 2011, banks and finance companies issued $169 billion in car loans to households with credit scores below 700. That was up 26% from 2010, though still down 32% from before the financial crisis, according to Equifax. Car loans to households with credit scores above 700 were $207 billion in 2011, up 8% from a year earlier and up 12% from before the bust.

Many Fed officials say their efforts to reduce interest rates have been appropriate if imperfect. Elizabeth Duke, a Fed governor, said in an interview last month that central bank policies lowered rates for corporate borrowing and consumer loans, with broadly positive effects on the economy.

Fed policies have also helped to push stock prices higher, which spurs growth. The Journal examined 18 instances when new Fed measures were either announced or foreshadowed since November 2008, the time of the central banks' first bond-buying program.

The S 500 rose by 0.7% on average during days of Fed news. The average increase in the index on all other days was much smaller, 0.05%, over the same period. Here, too, the spoils of easy money were unevenly divided: Wealthy households hold a large proportion of the nation's stocks.

The benefits of Fed policies are being spread broadly in other ways, however. The cheaper dollar, which since 2007 has dropped 4% against a broad basket of other currencies, is making exports a bit easier to sell abroad and, by extension, helping create blue-collar manufacturing jobs in the U.S.

But credit is the most important and most direct channel through which Fed policies affect the economy. The problem for the Fed is that the pipes in the financial system through which its easy money travels are clogged.

An April Fed survey found that 83% of banks were less likely to approve a new mortgage for a household with a low credit score of 620 and a 10% home down payment than they were in 2006, even a loan guaranteed by Fannie or Freddie.

'This is a big limitation on the potential effects of monetary policy,' Charles Evans, president of the Federal Reserve Bank of Chicago, said in an interview last month. 'Normally we'd have a very large refinance boom. People would be able to trade in their high-interest-rate mortgage for lower ones and their mortgage payment would go down. That would put more spending power in the hands of anybody in a position to do that. That would increase aggregate demand. That is the way it is supposed to work.'

Fed officials triggered a spat with Republican lawmakers earlier this year when they released a paper suggesting ways Congress and regulators could spur refinancing and ease credit to households not getting it. The Fed, for instance, urged regulators to allow Fannie and Freddie to waive fees and take on more mortgages. Some Republicans accused Mr. Bernanke of meddling in legislative affairs and taking the side of the White House.

Research shows how Fed efforts have yielded uneven results. A 2010 study by Paul Willen, a researcher at the Federal Reserve Bank of Boston, and Andreas Fuster, a New York Fed economist, found the Fed's mortgage purchase program in 2008 and 2009 led to a tidal wave of refinancing, but mostly by households with superior credit records.

Households with credit scores above 760 saw a sevenfold increase in refinancing after the Fed launched a $1.25 trillion mortgage-purchase program, while refinancing doubled among households with scores below 700, according to the study. A credit score near 800 is considered excellent, while scores in the 600s reflect some late payments or other past financial trouble.

'You want the money to go to people for whom credit is an issue, and those are exactly the people to whom credit isn't going,' Mr. Willen said. 'Monetary policy is having no effect on the vast majority of people.'

Since 2009, the Fed has launched several other mortgage bond-buying program and a similar bottleneck emerged. An analysis by Lender Processing Services Inc., a mortgage data research firm, shows that in April borrowers with credit scores of 760 or greater had paid more than 22% of their mortgages early, largely through refinancing, while borrowers with scores below 620 had prepaid less than 9% of their mortgages.

'Even though we have the greatest monetary policy stimulus in the history of the Fed, we really have not managed to lower the funding costs for a large swath of people,' said David Zervos, a bond strategist with Jefferies Inc., a Wall Street investment bank. He called Fed efforts 'monetary policy for rich people.'

Fed officials said they have a long-standing congressional mandate to minimize unemployment and inflation, not to micromanage the distribution of wealth, income or credit in the economy. 'That is expecting the Fed to do way more than it can possibly do,' said Ms. Duke.

The Fed's interest rate lever, Mr. Evans said, is a blunt instrument.

JON HILSENRATH