Mobil Oil Corp. President William P. Tavoulareas said yesterday that a federal judge who overturned his $2,050,000 libel judgment against The Washington Post has made "inconsistent determinations" on whether the newspaper exhibited malice in printing a 1979 article about his business dealings.

Tavoulareas said in a prepared statement that U.S. District Judge Oliver Gasch "on two earlier occasions" had addressed the malice question--whether The Post knew the disputed article was false or showed reckless disregard of the truth--and both times allowed the case to proceed and eventually go to a jury that decided in the oil executive's favor.

Gasch ruled Monday that while "portions of the article may have been 'slanted,' " there was "no evidence . . . to show that it contained knowing lies or statements made in reckless disregard of the truth."

The 63-year-old Mobil president said that "which of Gasch's determinations as to the malice issue is correct can only be determined by appeal," but he stopped short of saying that he would appeal the judge's ruling to the U.S. Court of Appeals. Tavoulareas has 30 days to file an appeal, but said no decision would be made until he and his lawyers study Gasch's decision more fully.

The two occasions to which Tavoulareas referred were Gasch's denial last summer, before the trial started, of the newspaper's request for a summary judgment, and later, when the judge allowed the case to go to the six-member jury without ruling on The Post's motion for a directed verdict in the newspaper's favor.

Tavoulareas said that even though Gasch overturned the jury's verdict, its "unanimous findings that the article was defamatory and false stand unchallenged."

Gasch said in a footnote of his 23-page opinion that since he had found "that there was no proof of actual malice," he did "not have to address this question of the truth of the Nov. 30, 1979 story directly." The article detailed Tavoulareas' involvement in the creation of a London-based shipping firm run by his son, Peter.

Tavoulareas also criticized Post executive editor Benjamin C. Bradlee for a comment he made after learning of Gasch's ruling.

"I fail to understand what Mr. Bradlee meant by his comment that 'It's a great day for newspapers everywhere,' unless he meant that it is a great day when a newspaper can publish with impunity an article which, in Judge Gasch's words, 'falls far short of being a model of fair, unbiased, investigative journalism,' and which a jury has concluded was false and defamatory."