U.S. produced alcohol fuel for autombiles is being promoted by politicians and others from the grainfields of Nebraksa to the forests of Maine as one way to reduce America's dependence on foreign petroleum.

Most motor vehicles can run on a blend of gasoline with 10 per cent alcohol - sometimes called gasohol - and without engine modification, experts say. Better yet, alcohol is less polluting than gasoline and can be distilled from readily available resources like coal, wood, wheat, sugarcane and even garbage produced in this century.

Fuels containing larger percentages of alcohol, or straight alcohol, can be burned in engines that have been modified at costs estimated between $50 and $100 per engine.

So far alcohol has proved too expensive for widespread use as an automobile fuel, but this appears to be changing as gas prices rise. The U.S. Energy and Development Administration also notes alcohol provides an emergency fallback should Mideast oil supplies be cut off.

Despite the appeal of alcohol fuels, they are not without problems. A recently completed road test on state vehicles in Virginia showed that alcohol blends got slightly worse mileage than straight unleaded gasoline and also caused some engine problems, especially in cold weather.

But other tests - especially in Nebraska, which has an advanced gasohol program - show slightly better mileage with gasohol than with unleaded gasoline and with few or no engine problems.

Richard Merritt, a private energy consultant in Bethesda who specializes in gasohol, said that when distilleries are built and economies of scale come into play, gasohol will become economically feasible.

Merritt envisions a nationwide use of gasohol that will within a few years achieve a 10 per cent cut in Americans need for imported petroleum.

The U.S. Senate recently approved legislation funding alcohol fuel research and guaranteeing loans for four pilot distillery projects. House approval is expected.

Others bills before Congress would provide for repid amortization of alcohol fuel plants, reduced federal excise taxes on alcohol fuels and set up experiments using fleets of federal vehicles.

Midwestern states want to sell alcohol made from grain, Maine wants to sell wood alcohol and several Southern states are said to be interested in selling alcohol distilled from sugar beets and sugarcane.

"I'd be surprised if alcohol is the ultimate answer to our energy problems but it's a big factor," said Robert Willmore, an aide to Sen. Car T. Curtis (R-Neb.), who introduced the Senate legislation.

A spokesman for the California Air Resources Board, which stringently controls auto emissions in the state, said board members are "very enthusiastic" about alcohol fuels because of their low emissions, but are waiting for costs to fall.

Charles R. Fricke, administrator of Nebraska's gasohol committee, estimated that if a full-scale program were set up in the state, complete with distillery, the alcohol would sell for $1.10 a gallon.

A private company is going forward with plans to build such a distillery. Nebraska has been experimenting with gasohol since 1971, and last month the legislature unanimously approved a 5-cent a gallon tax credit for motor fuels containing 10 per cent pure grain alcohol.

Nebraska officials say the credit makes gasohol competitve with gas and that test sales of gasohol in the state found wide consumer acceptance.

Proponents of gasohol claim its nationwide use would enable the U.S. to meet President Carter's energy goal by 1985 of reducing gas consumption by 10 per cent belwo current levels.

There are two common types of alcohol with different costs and properties that Merritt said probably will be blended half-and-half to provide the alcohol content of any gasohol.

Methanol or wood alcohol is made from resources like wood; coal, of which the United States is said to have a 300-year supply, and natural gas, billions of cubic feet of which are now "flared" or burned off daily as waste in Middle Eastern oil fields. Methanol is highly toxic.

Ethanol or grain alcohol, which is used in alcoholic beverages, is made principally from agricultural products. It is more expensive than methanol but blends more easily with gasoline, Merritt said.

Methanol has about half, and ethanol about 70 per cent the energy per gallon that gasoline has - meaning that bigger fuel tanks on cars running on straight or high percentage alcohol blends would be needed, according to Merritt.

This also means that methanol, for example, would have to cost half what gas costs to provide the same mileage per dollar.

But paradoxically, alcohol fuels make engines more powerful and have long been used as racing car fuels. Daimler-benz engineers testing cars on pure methanol found that engine output increased, provided that injection equipment would double the quantity of fuel reaching the combustion chambers.

Special starting devices were also needed, the engineers found, because cold weather affected the starting of the engine. They also recommended pressurized fuel tanks to keep the alcohol from evaporating and other special materials to resist the "chemically aggressive" alcohol.

On the other hand, the car needed no special antipollution equipment and the pure alcohol proved to have "an appreciably higher antiknock value" than gas.

Other auto manufacturers, including Volkswagen, are conducting extensive tests with alcohol fuels and blends.

While testing of alcohol fuels is going on widely, perhaps the most negative report has come from the American petroleum Institute, which represents large and small oil companies.

A booklet distributed by the institute is a detailed compendium of engine retuning problems, high costs, bad starts, bad mileage, bad driveability and engine damage when alcohol fuels are used.

ERDA has been charged by alcohol fuel advocates with taking a neutral and even blase attitude toward alcohol fuels. But a recent report by ERDA's Alternative Fuels Utilzation Branch seems to take a generally favorable view.

The report concluded that blends and straight alcohol are "feasible" as fuels, with the only major problems appearing to be fuel volatility - which causes problems like vapor lock - and bad starting at cold temperatures.

The report also concluded that 10 per cent blends of alcohol offer no significant changes in emissions or mileage.

Michael Sprinkel, and engineer with the Virginia Highway and Transportation Research Council; said that changing economic conditions may eventually make blends feasible.

He said that if he could show alcohol blends got better mileage, the state highway department might use alcohol fuels widely, "but the way our data's going to come out there's no way they're going to implement it."

The Virginia tests used our pairs of vehicles: one straight unleaded gas, and the other on a blend containing from 5 to 20 per cent methyl alcohol made from natural gas and costing about 50 cents a gallon.

Sprinkel said that "very slight alterations" had to be made in a couple of the alcohol-burning vehicles. "We had to adjust the carburators some . . ."

In addition, Sprinkel said that at colder temperatures the gasoline and alcohol tended to separate, which caused runing problems and meant that the vehicles could use only 5 per cent alcohol in the winter.

"This is a real problem," he said. "It complicates the issue. You need to retune you engine for the 5 per cent alcohol and then for the 15 per cent (in warmer weather)."

Sprinkel said that in each case, the vehicles using gasohol got worse, but "not significantly worse," mileage. Sprinkel's data will be published this summer.