Wholesale gasoline differentials jumped 9 cents on Wednesday after the U.S. Energy Information Administration reported a 1.78-million-barrel draw last week on West Coast gasoline stocks, traders said.

The draw comes as August-delivery gasoline blended to meet California's strict environmental standards is nearing expiry, expected no later than Monday, traders said.

August California gasoline traded on Wednesday morning at a 2-cent premium to September NYMEX RBOB gasoline. On Tuesday, California gasoline finished at a 7-cent discount.
 September-delivery California gasoline sold at 15 cents on top of the October NYMEX RBOB gasoline contract, a gain of 11 cents.

Traders scrambled to find a California refinery with a breakdown. No such malfunctions have been reported since Aug. 10, however, when Exxon Mobil Corp's (XOM.N) 149,500-barrels-per-day Torrance plant reported one.

By the end of last week, Exxon said the Los Angeles-area refinery was back to normal operations.