Visitors to Hawaii will find themselves paying about 10 cents more a gallon for gasoline than they did in December, following the expiration of a 10-cent-a-gallon tax credit at the end of 2006. Drivers headed to the pumps on Sunday to top off in advance of the anticipated pass-through of the additional tax, and a spot check of stations the first day of the new year saw the increase duly posted. Consumers on Oahu also are paying 4.5 percent in excise tax on all taxable purchases this year, an increase from the former 4 percent; that extra half-percent is going to the city and county of Honolulu for transit funding. The excise tax remains at 4 percent in the state's other three counties.