In the July poll, which followed a weaker-than-expected jobs report, the median forecast showed a 70 percent chance of QE3.

"Better figures in July are consistent with our view that job growth and activity will improve in the third quarter, and we expect that to be enough to keep them on hold," said Dean Maki, chief economist at Barclays Capital.

But many respondents cited underlying weakness in Friday's data, including a rise in the jobless rate to 8.3 percent and revisions showing employers hired fewer workers in May and June than initially reported, as justification for more Fed action.

"The headline number was better but the report was pretty soggy beneath the surface," said Ward McCarthy, chief financial economist at Jefferies & Co, who sees an 80 percent chance of more Fed stimulus. "The labor market, like the economy, is moving forward, but it's a frustratingly slow process."