For the last 3 1/2 months, Herman Sillas Jr., the U.S. attorney in Sacramento, has been in a position that some describe as twisting slowly, slowly in the wind.

Last Dec. 20, the Justice Department recommended to the White House that the popular Hispanic leader in California be fired because he had flunked two lie detector tests about allegedly taking a bribe. The alleged bribe took place in 1974, as Sillas was about to take a state job.

The White House has taken no action on the matter. Michaal Cardozo, of the White House counsel's office, said last week that the recommendation was still under consideration, but declined to say why it was taking so long to resolve.

Some Justice Department officials have expressed concern privately that the lack of action could appear to be politically motivated because of Sillas' high standing in the Hispanic community.

Attorney General Benjamin R. Civiletti had to recuse himself from the case because he interviewed Sillas last fall about becoming commissioner of the Immigration and Naturalization Service. Several Hispanic groups issued strong statements in support of Sillas in mid-January, after The Washington Post reported the firing recommendation.

Cardozo denied politics was a factor in the delay. "Anyone who knows Lloyd Cutler [the White House counsel] knows that's not how he would operate, not on a matter that affects a man's integrity."

Cardozo said that he couldn't say when the issue would be resolved, but added, "There's a process under way. We haven't neglected this matter."

Top Justice Department officials have been reluctant to push the White House on the matter.

The recommendation that Sillas be dismissed was made by acting deputy attorney general Charles F. C. Ruff the day he left office. The new deputy, Charles B. Renfrew, said he isn't interested in pursuing resolution of the case because the factual decisions were made before he arrived and he has more than enough to keep him busy.

"I'm the new boy in town," the former federal judge from San Francisco said. "I don't know that I'm supposed to go around rattling cages."

The bribery charges against Sillas surfaced in late 1978, more than a year after he became U.S. attorney. Richard T. Workman, an alleged con man, claimed he gave Sillas $7,500 through a conduit to get his auto dealer's license reinstated in 1974, according to sources. Sillas was appointed California director of motor vehicles a short time later.

Workman never did have his license returned, and didn't go to authorities with the bribe claim until he was in jail on fraud charges and seeking favorable treatment, sources said.

Authorities were skeptical of the allegation until Workman passed three lie detector tests. Last November Sillas took a polygraph to refute the charges and failed. He took another in December and flunked that one, too, sources said. After he refused suggestions that he resign, Justice officials made the recommendation that he be dismissed.

In a brief phone interview from Sacramento, Sillas said of his future: "I presume it will be resolved sometime." He declined to comment on his feelings about working under such a cloud. He said his relations with the FBI are good. "We're fighting crime," he said.