NEW YORK (TheStreet) -- A rate hike from the Federal Reserve is inevitable, but the unanswered question of 'when' proved too much uncertainty for investors on Wednesday.

Stocks whipsawed from deep losses to the flatline and back to losses in the afternoon session after minutes from the most recent Federal Open Market Committee kept things ambiguous, while a number of high-profile detractors made the argument against pulling the trigger too soon. 

The S&P 500 was down 0.81%, and the Nasdaq slid 0.80%. The Dow Jones Industrial Average dropped 0.93%, or 162 points.

The need for a rate hike was "approaching" but conditions for an increase had not yet been achieved, Fed members said in the July minutes of the Federal Open Market Committee meeting. The meeting's tone suggested a September rate hike wasn't off the table, though.

"Most judged that the conditions for policy firming had not yet been achieved, but they noted that conditions were approaching that point," the minutes read. "Participants observed that the labor market had improved notably since early this year, but many saw scope for some further improvement."

The Fed has played coy on giving any solid indication of when a move off of crisis-level rates would occur, but the majority of economists agree that action will be taken at least by the end of the year as the labor market continues to improve among other signs of an economic recovery. 

"We look at the rate hike decision in terms of probabilities," Scott Wren, senior global equity strategist at Wells Fargo (WFC) Investment Institute told TheStreet TV. "Coming into the release of these minutes, we said there's a 30 percent chance of a September liftoff and 50 percent chance of rate hike in December, but after these minutes, I think we're going to lean harder towards December."

If the Fed chooses to hike rates in September, it would mark the first time rates have moved above the zero to 0.25% range since December 2008. Members argued that delaying a hike could push inflation higher, though a few detractors noted that was unlikely given the strong dollar and low oil prices.

The minutes of the July meeting were released 20 minutes ahead of the 2 p.m. EDT scheduled time after the embargo was broken, the Fed said.

Markets were under pressure earlier in the day as investors speculated as to when the Fed will hike rates, and whether a hike is premature, caused jitters. Earlier in the day, Narayana Kocherlakota, president of the Minneapolis Fed, argued against a rate increase.

Raising rates "would create profound economic risks for the U.S. economy," he wrote an op-ed in The Wall Street Journal. "Given the prevailing economic conditions, higher interest rates would push the economy away from the FOMC's economic goals, not toward them."

Jeffrey Gundlach, co-founder of investment firm DoubleLine Capital, backed up Kocherlakota's argument. Speaking with CNBC, Gundlach noted that hiking rates would be detrimental to the economy given the current price of junk bonds.

"To raise interest rates when junk bonds are nearly at a four-year low is a bad idea," he said. "It opens the lid on a Pandora's Box of a tightening cycle."

Weaker-than-expected consumer inflation also highlighted the danger in the Fed hiking too soon. U.S. consumer prices nudged 0.1% higher, according to the Bureau of Labor Statistics, half the increase economists had expected. Higher housing costs drove the reading higher in July, while the remainder of factors such as energy and food costs remained soft.

"The very muted ... gains in both headline and core CPI in July will certainly give the Fed pause for thought in whether to raise interest rates or not at the next FOMC meeting in mid September," said Paul Ashworth, chief U.S. economist at Capital Economics. "On balance, we still think the Fed will go ahead and raise rates in response to the cumulative improvement in labor market conditions. But the decision is finely balanced."

Crude oil posted significant declines, sending energy stocks spiraling lower. Crude oil stocks increased 2.6 million barrels in the week ended Aug. 14, according to the U.S. Energy Information Administration. Economists had expected a decline of 1.2 million barrels. West Texas Intermediate crude fell 4.3% to $40.80 a barrel on the news as commodity traders feared an extended imbalance in supply and demand.

The steep decline hit the energy sector hard. Among the worst performers, Exxon Mobil (XOM) , Chevron (CVX) , and ConocoPhillips (COP) dropped some 2% each. The Energy Select Sector SPDR ETF (XLE) slid 2.5%.

In earnings news, Lowe's (LOW) recouped an earlier drop despite reporting net income of $1.20 a share, 4 cents below estimates. However, revenue of $17.3 billion climbed 4.2% from a year earlier and came in above analysts' estimates.

Staples (SPLS) slid 0.07% after reporting a quarterly sales decline of 7.6% at North American stores and online and guiding for a current-quarter sales decline. Earnings of 12 cents a share matched expectations.

Target (TGT) shares rose 0.85%, erasing earlier losses, after the retailer beat quarterly expectations on the top- and bottom-line and increased full-year guidance. The company expects 2015 earnings between $4.60 and $4.75 a share, up from a previous forecast of $4.50 to $4.56.

Hormel Foods (HRL) rose 1.5%, after dipping earlier in the session after reporting a mixed quarter. The food-processing company earned 56 cents a share, a penny above estimates, while revenue sank 4% to $2.19 billion. However, Hormel raised its full-year earnings estimates to as high as $2.63 a share on improved profitability in its meats division.

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