Speculation about possible shortages drove wholesale gasoline prices higher Friday, while a public interest group sought to dispel fears of shrinking supplies as the peak summer driving season approaches.

In an unusually hectic session on the New York Mercantile Exchange, traders bid up gasoline prices amid reports that refiners on the West Coast temporarily will receive smaller quantities of crude due to disruptions in shipments from a major Alaskan port.Other petroleum prices were pushed along by the buying momentum in the gasoline futures pits, but the rally lost energy in the afternoon and crude oil finished lower.

Unleaded gasoline for April delivery rose 2.12 cents to settle at 65.31 cents a gallon. At one point during the busy session, the contract was up more than 41/2 cents a gallon.

This week wholesale gasoline on the West Coast has surged to more than $1 a gallon, up about 15 cents since an Exxon tanker rammed a reef causing the country's worst oil spill.

The accident forced the closure of the port in Valdez, Alaska for four days and created a massive oil slick that had spread over 600 square miles by Friday.

Among other refined petroleum products traded on the exchange, the April heating oil contract settled at 56.89 cents a gallon, up 0.71 cent for the day.

Crude oil prices headed down when traders decided to sell so they could collect profits amassed during the market's runup. The selling started in the afternoon as rumors circulated in the market that Alaskan tanker traffic was returning to normal.

The May contract for West Texas Intermediate, the benchmark grade of U.S. crude oil, lost 62 cents, settling at $20.19 a barrel.

"It was extremely emotional trading today," said Mary L. Haskins, a vice president at Drexel Burnham Lambert Inc.

William Byers, an energy market analyst at Bear, Stearns & Co., said "nearby supplies are extremely tight on the West Coast and that is having an effect all over the country."