An exotic fuel called "The Anderson Difference" helped boost John B. Anderson from a political unknown into an independent presidential candidate whose appeal last summer appeared to threaten both President Jimmy Carter and Ronald Reagan.

Anderson set himself apart from the jpack 10 months ago with his proposal for a 50-cents-a-gallon tax on gasoline, and his chip-on-the-shoulder advocacy of controversial issues, among them gun control, the Equal Rights Amendment and opposition to a constitutional amendment prohibiting abortions.

But in the final month of the campaign, it has become clear that "The Anderson Difference" has not made enough of a difference to voters who were once interested in the Illinois congressman, but are now lining up behind Reagan and Carater. The polls show his supporters being pulled away like iron filings drawn to a more powerful magnet.

Anderson's economic program was designed to create a constituency out of moderate Republicans and former supporters of Sen. Edward M. Kennedy (D-Mass.) and other liberals who still bear a grudge against President Carter but will not cross over to Reagan.

He accuses Carter and Reagan of ducking the hard choices that he sees ahead for the country. His speeches are often sermons on why the public must sacrifice by paying higher energy prices and higher taxes to avoid critical problems in the future.

Anderson believes that a crippling disruption in oil shipments from the Persian Gulf is inevitable sooner or later because of the unsettled antagonisms in the region. He calls for the federal government to fill its strategic oil reserve and impose a 50-cents-a-gallon gasoline tax, which eventually could cut gasoline consumption by 10-15 percent from current levels, according to his advisers.

The money raised from the gasoline tax would permit a cut in Social Security tax payments of $625 a year per taxpayer, says Anderson. The gasoline tax is rough medicine, he says, but it is a way of keeping the Social Security trust funds solvent in the future, a problem his opponents are ignoring, he says.

Except for this reduction in Social Security taxes, Anderson opposes a major tax cut in 1981, challenging the main feature of both the Carter and Reagan campaign planks on the economy.

"We must resist the impulse to cut personal income taxes in this election year," he tells audiences.

In Anderson's view, both the Carter and Reagan campaign tax-cut plans would invite more consumer spending, adding to inflation. Even the Carter plan, which steers more of its tax benefits toward business than to individuals, is still inflationary because it adds billions more to the federal deficit, Anderson says.

"Let's get it straight. We all want tax relief, but inflation is America's most chronic and cruel tax. In the last year alone, it has cut the average real incomes of an urban worker by more than $1,000 . . . Carter's record on inflation is one of demonstrated failure; Reagan's fiscal program, by contrast, is a blueprint for still higher inflation and interest rates.," an Anderson position paper on economic issues says.

Sacrifice "is not an option. Our economic future is being sacrificed right now," Anderson says.

More gradually than his opponents, Anderson would reduce taxes on individual savings and corporate capital spending.

To restrain inflation without continuing high interest rates, risking another recession, the federal government must establish a strong program to limit wage and price increases, Anderson says.

As president, he would ask business and labor leaders to help set goals for wage and price increases and design a plan that would either reward companies that meet the targets by reducing their taxes, penalize those who don't by raising their taxes, or both.

An Urban Reinvestment Trust Fund would be established to help deteriorating cities, particularly in the Northeast and Midwest, rebuild sewers, water systems, roads and bridges -- the essential services that must be present before businesses will agree to expand operations in urban areas. The fund would be financed by taking 45 percent of the revenues from federal alcohol and tobacco excise taxes. After a three-year phasein period, the fund would distribute $3.8 billion annually to the neediest cities.

A Coal Export Authority would be established to speed up -- and finance, if necessary -- an expansion of port facilities to end the transportation bottlenecks that are blocking large shipments of U.S. coal overseas.

An Industrial Development Administration would be created in the Commerce Department and given authority to offer loan guarantees and other financial aid to companies and industries where that aid will promote new technology and help promising new industries expand.

Anderson defends his proposals as an honest program whose costs have been documented in an "Anderson Budget" released by his campaign staff -- and he notes that Reagan has not spelled out what his Republican budget would look like.

The irony of the Anderson campaign is that despite the importance of his platform to his cause, he has talked less and less about it as the campaign has neared the end.

He says he has been obliged to join in the campaign name-calling this month, demanding a place in the Carter-Reagan debate and complaining loudly when he was excluded. Lately, he has stepped into the debate over the administration's handling of the hostages in Iran.

"I have really tried to be positive, but if you want to be reported, you have to stand up and criticize your opponents," he said in an interview.

They have largely ignored him. From Reagan's standpoint, the Anderson program is a liberal formula for governmental meddling in the private sector.

Carter aides call Anderson's program naive, put together with too little regard for political realities.

The Anderson platform, for instance, notes that outmoded U.S. ports can't come close to supplying the booming demand for U.S. coal overseas, where it is seen as a safer substitute for Middle East oil. Anderson's coal agency would be instructed to overcome the environmental obstacles that prevent dredging operations to widen coal-shipping harbors.

But local governments and private citizens would have something to say about that, too; and Congress, in its present mood, would be unlikely to hand over the power Anderson is seeking for his Coal Export Authority.

Anderson wants to have a top-ranking labor-management committee outline a new wage and price restraint program and then back up the program with tax cuts and tax penalties.It is a concept that has interested academic economists for some years; and Anderson says he wouldn't just talk about it, he would do it.

But many industry and labor leaders are hostile to the notion of a tax-based incomes policy, which presumably would be enforced by the Internal Revenue Service. They don't want the IRS intruding into decisions about how groups of workers within the same company are paid. Some experts doubt that the leaders Anderson would call on would participate in such a program.

For whatever reasons, Anderson's program hasn't reached enough of the voters this year. And while he is not conceding anything, he has begun to look past Nov. 4 to ways of keeping himself and his program in front of the public.

"If one of them [Carter or Reagan] is elected and Congress is so foolish as to go along with the kind of tax programs they have recommended, and we do -- as I believe we will -- see a resurgence of inflation, it will be possible to go back and point these things out. Not simply with an 'I-told-you-so' attitude, but as a better alternative that people would maybe be more apt to listen to," Anderson said.

In time, when the Middle East blowup he expects causes a true fuel crisis, his platform will look better to more people: "When that interruption comes, then I think people with gasoline lines will listen far more attentively to the idea of a large gasoline tax as a way of reducing dependence on foreign oil."

"I'm certainly not going to retire to the side of the road and live out a hermitic existence" if one of his opponents wins, he said.

"I expect to be very active, very vocal as a commentator on public policy."

Hundreds of people have worked in the Anderson campaign. Thousands have contributed to it -- more than $9.5 million so far, he noted: "You just don't shut the book and write an epitaph to all that and forget about it."