Northern Virginians came away empty-handed today when a Senate committee approved a $263-million package of gas- and highway-user taxes without pledging any of the revenues toward mass transportation.

"We have a problem here," said Sen. Adelard Brault (D-Fairfax), after fighting a losing battle on the Senate Finance Committee to commit an extra $15 million to the D.C.-area Metro system.

Brault withheld his vote in protest, but the tax package--centered around a 3 percent tax on wholesale gasoline sales--did win the support of two other Northern Virginia senators and cleared the panel by a vote of 10 to 4.

The bill, sponsored by Finance Committee chairman Sen. Edward E. Willey (D-Richmond), is the first of many tax measures expected this year to address the financial problems of the state Highways and Transportation Department.

The department faces a $360-million deficit over the next two years because of lost revenue. A drop in gasoline consumption due to increased use of smaller cars has caused a drop in revenues collected from the state's current 11 cents-per-gallon gas tax.

Democratic Gov. Charles S. Robb has committed himself to an increase in highway revenues this year, but so far has stayed aloof in the battle to enact new taxes. The Robb administration supports adding another $8 million to the $14 million earmarked for Metro in the state's 1982-1983 budget.

The Willey bill faces strong opposition first on the Senate floor and then in the House of Delegates, where lobbyists for the oil companies, trucking industry and other opponents are expected to concentrate their efforts. "It's a tough bill," said Senate Majority Leader Hunter B. Andrews (D-Hampton). "It's going to be a whole new ball game in the House."

Next week, the House Finance Committee will start considering a bill of its own, sponsored by chairman Del. Archibald Campbell (D-Wythe), which would levy a 3-cents-per-gallon tax at the retail level and increase various license and registration fees.

For the Northern Virginia legislators who came here this year pledged to stand united in the fight for Metro money, the battle has shifted slightly. Sen. Clive DuVal (D-Fairfax) and Sen. Charles Colgan (D-Prince William) were the only two committee members today to support Brault's amendment, but they broke ranks with their Northern Virginian colleague later and voted for the final package.

DuVal said he supported the Willey bill so that the powerful Finance Committee chairman "would owe us one" when the state budget comes before the panel.

Brault predicted that the Northern Virginia senators would be divided over the Willey bill: "We'll probably be free spirits on this one," he said. "The time for united action will be when a bill comes back over from the House."