Hawai'i motorists may want to wait until Sunday to fill 'er up. That's when an 11-cent-per-gallon tax break on ethanol-blended gasoline will likely be reinstated, which should lead to a corresponding drop in prices at the pump.

The state has some of the highest gas prices in the nation. Prices in Honolulu for regular range from $3.19 to $3.35 per gallon, according to gasbuddy.com, while in Kahului gas is selling for $3.75 per gallon, in Hilo from $3.37 to $3.40 per gallon, and in Lihu'e for $3.34 per gallon.

"They'll see a drop on July 1," said Nathan Hokama of Tesoro Hawaii, an independent fuel refiner that also owns about 30 retail stations on O'ahu, Maui and the Big Island.

Whether prices remain at lower levels will depend on fluctuating crude oil prices and local competition, he said.

The tax break on ethanol-blended gasoline expired Jan. 1 but was revived by the Legislature this year. If Gov. Linda Lingle, who supports the tax break, signs it this week, it will take effect July 1. If she doesn't sign it by Sunday, the tax break will take effect July 11.

It is estimated that restoring the ethanol tax break would cost the state $32 million in lost revenue. The total tax at the pump would fall to 50.2 cents a gallon, including federal, state and county taxes, with the break.

According to the legislation, the ethanol tax break would expire at the end of June 2009. As part of the bill, lawmakers also created a fine of $100,000 for gas producers, wholesalers and retailers that increase their profit margins as a result of the tax break. It also would be considered an unfair or deceptive trade practice.

With the average automobile fuel tank size of 15 to 18 gallons, the savings for consumers could range from $1.65 to $1.98 per fill-up.

But car owners might not want to risk running on empty while waiting for cheaper prices Sunday, said Dale Manning of the Goodyear auto service center in Kane'ohe. "With fuel-injector cars, you don't want it to run too low.

"When you get all the way down to the bottom of the tank, there is a higher concentration of junk. Typically, your fuel filter will take it out, but you never know.

"And, you don't want to run out of gas."

Reach Christie Wilson at cwilson@honoluluadvertiser.com.