“Companies came into this period with extraordinarily high profit margins,” said Edward McKelvey, chief domestic economist at Goldman Sachs, “and some of the surge in raw material costs will be absorbed by lowering those profits.”

Still, the prevailing attitude that the economy could just keep absorbing higher oil prices is being tested  for the first time in nearly 30 years. Adjusted for inflation, a barrel of crude is now more expensive than it was in 1980, the previous peak.

“The conventional wisdom a couple of years ago was that oil did not have that much leverage over the economy,” said Daniel Yergin, chairman of Cambridge Energy Research Associates. “But now it plainly does. People are suddenly paying much more attention to their energy costs and trying to figure out how to manage them.”

Goodyear has kept its head above water in part by passing along some of the higher prices to dealers. The dealers, however, have not been able to pass along all of those increases to consumers and are absorbing the difference in lower profits.

Since last spring, the average profits of the nation’s corporations  from behemoths like Goodyear to small neighborhood retailers  have declined at an annual rate of nearly 6 percent, government data show.

Even companies that have been performing well in the economic downturn are sounding notes of caution. Take Costco, the discount retail chain, which offers a wide array of consumer goods, food, wine, furniture, appliances, beauty aids and much more.

Costco’s profit was up in the first quarter, but James D. Sinegal, the chief executive, says he is “starting to be confronted with unprecedented price increases” for the merchandise that Costco buys to stock its stores. His first response has been to buy in extra large quantities so that he has stock on hand to carry him through subsequent price increases.