There were some encouraging signs. Overnight, the national average for a gallon of regular gasoline saw an all-too-rare decline of 0.2 cents to $3.927, according to the AAA Fuel Gauge Report. The AAA uses prices compiled from more than 100,000 retail outlets by the Oil Price Information Service and by Wright Express.

In the 23 states with averages of $3.90 or above for a gallon of regular gasoline, 22 saw declines since Sunday. The average rose in Pennsylvania, the state that has been hardest hit by refinery closures and tightening supplies.

Two of those 23 states--Michigan and Indiana--have dropped below $4 a gallon since last week, reducing the number of states above $4 to eight. In California, the state where prices first began to drop, the average fell to $4.264 a gallon, off 4.3 cents since last week.

But the uncertainty over whether prices have peaked comes from the fact that 15 of the 23 states with the most expensive gasoline are still higher than they were at this time last week. Still, there was some guarded optimism among analysts.