Investors initially welcomed reports that OPEC plans another production increase in May to meet steady demand. Crude futures climbed higher, however, breaking a five-session streak of lower prices. A barrel of light crude settled 39 cents higher at $53.71 on the New York Mercantile Exchange.

Falling oil prices helped the major indexes post weekly gains for the first time in a month, but crude futures remain high and analysts warned that investors will need to see strong first-quarter earnings over the next few weeks for stocks to recover further. Ford's announcement fed doubts about whether corporate America can keep profits up in the face of high energy costs.

"Right now, you see the economy growing and things are looking pretty good, despite all the worries," said Hans Olsen, managing director and chief investment officer at Bingham Legg Advisers. "But while the economy is climbing that wall of worry, stocks are running right into it. We'll need to see some pretty good earnings down the road to overcome that."

According to preliminary results, the Dow Jones industrial average slid 12.78, or 0.12 percent, to 10,448.56.

Broader stock indicators were mixed. The Standard & Poor's 500 index was up 0.01, essentially flat, at 1,181.21. The Nasdaq composite index lost 7.23, or 0.36 percent, to 1,992.12.

Bonds rallied, with the yield on the 10-year Treasury note falling to 4.44 percent from 4.47 percent late Friday. The dollar lost ground against other major currencies, while gold prices rose.

Stocks fluctuated in and out of positive territory for much of the session, and volume was very light — signs of a market in a holding pattern as earnings reports start to come in.

"Most people are very risk averse. They don't want to make a mistake right now, so you see people reacting, not anticipating," said Paul McManus, chief investment strategist with Independence Investments. "People are just going to be sitting at their desk, reading a bunch of earnings reports, gauging who looks good through the summer and then they'll take positions."

Ford weighed on the markets as the automaker said higher expenses and a difficult market would cut into its quarterly and full-year profits. Two brokerages downgraded the company's stock, and Standard & Poor's also cut its rating on Ford's debt. Ford tumbled 59 cents, or 5.4 percent, to $10.44, on the news; parts suppliers Delphi Corp. slipped 11 cents to $3.99 and Visteon Corp. dropped 27 cents to $5.23.

Dow industrial Microsoft Corp. added 3 cents to $24.97 after the company announced a settlement with computer maker Gateway Inc. over antitrust issues. Microsoft, which agreed to assist Gateway in its marketing efforts, said it would take a $550 million charge to cover the settlement. Gateway rose 8 cents to $4.16.

Verizon Communications Inc. fell 17 cents to $34.90 after the Dow component bought out MCI Inc.'s largest single shareholder, taking a 13.75 percent stake in the company and clearing the way for its $6.7 billion takeover of MCI, which gained 17 cents to $26.01. Qwest Communications International Inc., which had a $9.1 billion offer rejected by MCI, lost 11 cents to $3.82.

Aircraft maker Boeing Co. said Korean Air would order up to 20 of its new 7E7 Dreamliner jets in a deal estimated at $2.4 billion. Boeing rose 80 cents to $59.40.

Electronics retailer Circuit City Stores Inc. added 48 cents to $15.89 even after the company said fourth-quarter earnings fell due to intense competition and sharp price cuts over the holidays.

Declining issues outnumbered advancers by about 4 to 3 on the New York Stock Exchange.

The Russell 2000 index of smaller companies was down 3.58, or 0.59 percent, at 607.17.