AMMAN, JORDAN, OCT. 28 -- President Saddam Hussein today abolished gasoline rationing only nine days after it was announced and fired his oil minister.

Iraq said in explaining the move that the dismissed minister, Issam Abdul-Rahim Chalabi, had miscalculated the supply of chemical additives needed to make gasoline and engine oil. Chalabi had cited supposed shortages of these additives in announcing the rationing decision on Oct. 19.

The sudden reversal of the unpopular rationing measure, accompanied by Chalabi's dismissal, suggested serious disagreement within Saddam's government over management of the economic consequences of the Persian Gulf crisis. The Iraqi announcement also seemed to signal a shift from civilian to military control over the country's most important resource and the lifeblood of its army.

A presidential decree said the responsibilities of Chalabi, an oil executive who had been minister since 1986, were assumed by Industry and Military Industrialization Minister Hussein Kamel Hassan. Kamel, 32, the president's son-in-law and former bodyguard, is considered a member of Iraq's highest ruling circle and a key figure in its security apparatus and million-man military establishment.

Kamel was born in Tikrit, Saddam's birthplace and the hometown of many of the Iraqi leader's closest associates in the Baath Party government.

The announcement of the immediate lifting of gasoline rationing coincided with two rounds of conversations in Baghdad between Saddam and Yevgeny Primakov, a special envoy of Soviet President Mikhail Gorbachev. Primakov is on his second trip to the region this month seeking to organize a Soviet-sponsored peace initiative.

Primakov's visit, preceded by remarks from Gorbachev that Iraq was showing signs of flexibility, generated speculation that it might be the start of a diplomatic process that would halt what many fear is a countdown to war in the gulf. But the talks ended with no sign of progress, and the British Broadcasting Corp., quoting Soviet sources in Baghdad, said Primakov failed to budge Iraqi insistence on retaining its hold on Kuwait.

In Paris, where Gorbachev arrived late today for talks with French President Francois Mitterrand, Soviet Foreign Minister Eduard Shevardnadze indicated that Primakov's talks had not produced a breakthrough. "For the moment, there are not many reasons for optimism," Shevardnadze told reporters, adding he was still hopeful that the gulf crisis could be resolved peacefully, the Associated Press reported.

Primakov was scheduled to continue his peacemaking rounds Monday in Saudi Arabia, the center of a U.S.-led multinational military force arrayed against Iraq to press him into withdrawal.

Iraq's resort to rationing for gasoline and engine oil, supposedly because it was running short of additives such as lead and oxidation inhibitors, had been regarded as the clearest sign to date that the U.N. Security Council's economic embargo against Iraq was taking hold. It was the major piece of evidence cited by U.S. and other officials last week in hailing the embargo's effectiveness and predicting it would soon harm Saddam's military machine.

The embargo, which was imposed Aug. 6, has been regarded by many as the most effective alternative to war in forcing Saddam to agree to withdraw from Kuwait. But by reversing the gasoline rationing, Saddam seemed to be displaying confidence that his country and military establishment can continue operating for some time despite the blockade.

In announcing the measure Oct. 19, Chalabi specifically cited shortages of chemical additives previously imported and cut off by the embargo. But the official Iraqi News Agency reported that a meeting today presided over by Saddam concluded Chalabi's ministry made "miscalculations" about Iraq's supplies of the chemical additives.

"The solutions were presumed to be enough for a certain period, but it was evident that they were enough for double the period estimated by the Oil Ministry," INA said in a report on the gathering of what it described as experts from the oil and military industries. "In addition to that, experts and scientists of the Ministry of Industry and Military Industrialization stressed the ministry's capability of manufacturing the necessary imported solutions."

The ability of Iraq's domestic industry to make the chemical additives necessary to refine crude oil into usable products was not known. Chalabi told the Oct. 19 news conference they had been imported until now. In any case, Iraqi officials reportedly have looted Kuwaiti refineries of all kinds of supplies -- presumably including chemical additives -- since Baghdad invaded the country Aug. 2 and annexed it six days later.

Chalabi was quoted only this morning in the official Al Thawra newspaper as lamenting Iraqi motorists' "wasteful" driving habits, which he said were encouraged by low gasoline prices. The rationing plan, which went into effect last Tuesday, retained government-set prices at slightly over $1 a gallon.

Reports from Iraq have cited complaints from taxi drivers, private motorists and bus riders that the reduced fuel supplies disrupted transportation in Baghdad and between it and other cities. Heeding the complaints, Chalabi's ministry several days ago increased allowances for trucks and buses, and on Saturday loosened restrictions for private cars with large engines.

Chalabi had made clear that his rationing was designed to ensure supplies over the long term rather than respond to immediate shortages. He said military needs had been taken into consideration.

Iraq has been producing 300,000 to 400,000 barrels of oil a day, matching its internal consumption, he said. Before the gulf crisis, Iraq had been exporting in addition about 2.8 million barrels a day, making it one of the world's leading exporters.

Since then, however, the U.N. embargo has cut off the exports. U.S. and allied ships have blocked tankers with crude oil from entering or leaving Iraqi ports. Saudi Arabia and Turkey have shut down pipelines that carried Iraqi crude to ports on the Red Sea and the Mediterranean.

Meanwhile, U.S. Marines today boarded an Iraqi vessel in the Arabian Sea near Oman in the effort to halt supplies to Iraq, the U.S. Navy announced in Dhahran, Saudi Arabia. The Amuriyah, bound for Iraq through the Persian Gulf, refused to halt despite summons from U.S. and Australian ships. Cmdr. J.D. Van Sickle, a Navy spokesman, said the allied ships fired shots across the Amuriyah's bow and warplanes from the USS Independence aircraft carrier buzzed low in warning passes.

The Marine boarding party, which climbed down ropes from helicopters, found no banned cargo and the Iraqi craft was allowed to proceed, Van Sickle said.