Market talk is abuzz that the Federal Reserve will roll out an unorthodox stimulus tool known as quantitative easing in the coming days to spur a sagging economy.

Under quantitative easing — dubbed by many as printing money out of thin air — the Fed buys assets such as mortgage-backed securities or Treasury instruments from banks, pumping them full of liquidity with the aim of pushing long-term interest rates down to encourage investing and hiring.

Since November of 2008, the Fed has juiced the economy via two rounds of quantitative easing (QE1 and QE2), injecting a total $2.3 trillion worth of expansionary liquidity into the financial system.

Editor's Note: You Deserve to Know What Obama and Bernanke Are Hiding From Americans

Quantitative easing is used as a stimulus tool to spur the economy when interest rate cuts alone don't work, yet experts say QE1 and QE2 haven't done much to help and doubt a QE3 would do much good either.

Unemployment rates today stand at 8.2 percent, far above pre-recession levels of well below 5 percent, while the economy is barely moving along — the country's gross domestic product expanded 1.9 percent in the first quarter, down from an initial estimate of 2.2 percent.

Furthermore, critics contend, quantitative easing fuels inflationary pressures down the road, though some admit QE1 did loosen credit markets in wake of the Lehman Brothers collapse of 2008.

"In early 2009, on net, it was probably beneficial," Columbia University economist Michael Woodford, tells The Wall Street Journal.

"What's less clear is how much of an effect it has when financial markets are functioning more normally."

QE1 saw the Fed buy $1.7 trillion in mortgage-backed securities held by banks, while QE2 saw the Fed buy $600 billion in Treasurys from financial institutions.

Other experts agree easing now won't do much in that interest rates are already low.

"I'm not a big fan of more action on the Fed’s part. It worked to boost the stock market temporarily but we have reversed all the gains of the year on the stock market," former Hewlett-Packard CEO Carly Fiorina tells CNBC.

"More QE won't do any good," she adds.

Some point out that quantitative easing plants the seeds for inflation down the road, adding that interest rates have plummeted thanks to the European crisis, which has driven investors worldwide to the safe-haven 10-year Treasury note.

Hefty demand for U.S. government debt has pushed yields on the benchmark 10-year to record lows.

Furthermore, the Fed cannot protect the U.S. economy from an economic meltdown in Europe.

"A change in U.S. monetary policy at this juncture will not alter the situation in Europe," says James Bullard, president of the St. Louis Federal Reserve Bank, according to Reuters.

Other Fed officials agree, considering the inflationary impacts that could follow suit.

"Short of an implosion, I cannot support further quantitative easing," Dallas Fed President Richard Fisher says separately, Reuters adds.

Editor's Note: You Deserve to Know What Obama and Bernanke Are Hiding From Americans