House-Senate conferees failed yesterday to find an acceptable formula for giving President Carter the power to ration gasoline.

Meeting for the first time since the House approved a standby rationing bill just before the August congressional recess, the conferees stumbled over whether Congress should have advance veto power on a proposed rationing plan, something the administration opposes.

Ironically, the effort to give Congress such veto power came from Senate conferees, who were at the same time trying to make it easier for the president to impose rationing. The confusion apparently resulted from a failure by the administration to outline its position fully to Senate conferees.

House conferees, who went through the agony of the veto issue before approving the bill, are expected to reject the veto proposal when the conference meets again next week.

The only progress came when Senate conferees suggested that the rationing plan should be triggered when there is a 10 percent shortage of oil, rather than 20 percent as approved in the House bill. The administration opposes the 20 percent trigger, arguing that it is too restrictive.

Yesterday's session appeared to be a case of the senators not getting the word from the administration. When Sen. Peter Domenici (R-N.M.) argued that if a one-house veto didn't occur until the plan was to be implemented, as the House bill provides, "we'd have no say at all. At the point we'd implement anything," Sens. Howard Metzenbaum (D-Ohio) and J. Bennett Johnston (D-La) went along with his demand for an earlier one-house veto. In addition Domenici suggested one-house vetos of any amendments to the plan the administration might want to make.

An official said the administration remains opposed to a prior one-house veto. "Our position is that it is untenable and unworkable." But he said the administration hadn't discussed it with Democratic senators before yesterday's meeting because the administration didn't expect the issue to come up. Energy Secretary Charles Duncan called Johnston during the meeting, but at that point it appeared to be late if Johnston wanted to back off. "He's not ignoring the administration position, he's just trying to get a bill," an aide to Johnston said later.

After the House rejected Domenici's one-house veto proposal, he came back with a proposal that tied a lowering of the trigger for rationing to a one-house veto.

The House bill requires a 20 percent shortage of petroleum products for 30 days before gas rationing could be imposed, something the administration says would prevent the president from acting until there was a very severe emergency.

Domenici proposed that the president be allowed to impose gas rationing if there was a shortage of motor fuels of between 10 percent and 20 percent for 30 days, based on the seasonally adjusted average of the previous 12 months. As in the House bill, implementation at that time would be subject to a one-house veto. If the shortage exceeded 20 percent, no veto would be allowed. But Domenici insisted that Congress should retain the right to veto any gas rationing plan for use in such an emergency, and reiterated the one-house veto of the plan then.

House conferees tried to explain why the veto issue is so serious. Last May, the House defeated a gas rationing plan, after regional and special interests looked at the details and decided their interests would be hurt.

"You just won't get a gas rationing plan passed in the House if you need prior approval," Rep. Richard Ottinger (D-N.Y.) said. Absent an emergency they won't do it."

"The collective strength of lobbyists -- taxicab drivers, truckers -- who oppose it is much greater than the strength of those for it," Rep. Toby Moffett (D-Conn.) said.

Rep. John Dingell (D-Mich.) said the plan submitted in May was changed to suit the Senate, where rural interests dominate, but when big-city delegations in the House looked at it they rejected it.

Domenici argued that without a congressional veto until implementation, "We are getting out totally and leaving it up to the president."

Rep. Clarence Brown (R-Ohio) said, "We'll approve shooting every third driver, if we wait until a crisis comes along."

"If you don't want a rationing plan, this is a splendid way not to get it," Dingell said.

But an official said the administration would not accept Domenici's trade of a lower trigger in return for giving Congress a one-house veto and expected the House to reject Domenici's proposal.

The administration got significant support for lowering the trigger from the Senate, but this is also a sticking point for the House conferees who had to agree to a higher trigger to get conservative Democrats and Republicans to support the bill.

Conference chairman Sen. Henry M. Jackson (D-Wash.), told reporters the 20 percent trigger mechanism "is totally unrealistic," and predicted it would be lowered. Jackson also warned, "the danger of a cutoff [of Mideast oil] is as great as it's ever been. The lid can blow off at any moment. I think what we do here on rationing may well be imposed."

The House attached rationing to a bill giving the president authority for fewer conservation measures which the Senate had passed. Though the Senate approved rationing in May, it did not include rationing in the conservation bill, but is expected to approve some form of the House version.