Congress is suddenly rushing to set up a program to help the poor pay rising heating bills this winter without waiting for the windfall profits tax on oil President Carter wants to pay for them.

The Senate by voice vote approved $1.2 billion for the program yesterday and is expected to give final approval on a roll-call vote scheduled tomorrow after House and Senate conferees have had time to shape a final budget resolution to make room for it.

President Carter's proposal for creation of a special $20 billion fund for synthetic fuels production also moved a step ahead yesterday. The Senate approved the fund, 59 to 38.

The Senate Finance Committee, meanwhile, tentatively approved a formula for helping the poor pay for their fuel bills in future years with funds from a trust fund to be financed by the windfall tax.

And a House Appropriations subcommittee is to hold a hearing tomorrow on stepping up fuel aid for the poor, financed at $250 million in the regular Health, Education and Welfare appropriation bill earlier this year. Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) said he will testify and strongly urge a substantial increase in aid to help pay rising costs, which otherwise would force some to choose between food and warmth.

The administration has requested an extra $1.35 billion, but asked that it be conditioned on enactment of the windfall profits tax to soak up part of the profits the oil industry will realize as a result of Carter's action phasing out price controls on domestic oil.

The Senate provision contains no such condition, because there is no certainty that the tax will be on the books in time to get the money out before cold weather sets in. The energy trust fund that is to be created and fed by the windfall profits revenue is, however, expected to be the ultimate source of funds for fuel aid to the poor.

Various bills authorizing more fuel aid for the poor have been introduced and hearings held but none has reached the floor of either house yet.

Sen. Jacob K. Javits (R-N.Y.), who has led the fight for fuel aid to the poor, told the Senate it can't wait any longer for authorizing legislation because even if the money is voted now it will be the first of January before any money reaches the poor to pay for heat.

On Monday, Javits offered an ammendment to the Interior Department appropriation bill, which contained $20 Billion to encourage production of synthetic fuels, tapping that fund for $1.35 billion to help the poor pay their fuel bills. The Senate rejected it, 43 to 47, as a budget-buster and irregular procedure.

But Javits was back yesterday with a new proposal for $1.2 billion that would not touch the synfuels fund. This time the Senate, apparently not wanting to appear heartless, approved it tentatively by a voice vote that will be put a record vote tomorrow. It is expected to be approved.

The amendment providing $20 billion for synfuel development would make only $2.2 billion available immediately in the form of federal loans and subsidies. The balance would have to be authorized and appropriated by Congress later.

The Javits fuel-aid program would be administered by the Community Services administration under guidelines to be worked out. The senate made it clear in debate that it expected more aid to go to the North than to the South and that the fuelaid program should be for heat and not other energy needs.

The administration has estimated the funds it sought would give about $100 to a poor single person and $200 to a poor family during the coming winter.

The Senate Finance Committee tentatively approved a formula that provides for fuel-aid payments to be sent to recipients of welfare, food stamp and Supplemental Security Income assistance through federal and state agencies. States could, in the alternative, devise their own plans for the aid program.

Revised estimates now put receipts from the tax at $76.9 billion over 10 years. The tentative plan is to give $20 billion of this amount in fuel aid to the poor and $10 billion in noncash tax credits to households with income between welfare levels and $20,000 a year.

In another energy action, the Senate Energy Committee approved a $650 million authorization to be used over five years for loan and price guarantees to encourage production of gasohol. The long range goal is that by 1990 10 percent of all gasoline consumed to be a mixture of gas and alcohol to save oil.