A member of the Daughters of the American Revolution who was disciplined by the society last year for speaking out against what she termed a racially discriminatory bylaw filed suit against the DAR in D.C. Superior Court yesterday, charging that the organization violated her civil rights.

Meanwhile, Sen. Howard M. Metzenbaum (D-Ohio), has asked the Internal Revenue Service to investigate the DAR's tax-exempt status in light of allegations that the group discriminates against blacks.

The woman who filed yesterday's lawsuit, Faith K. Tiberio of Sherborn, Mass., was found guilty at a DAR hearing in October of "conduct calculated to disturb the harmony," "conduct injurious to the good name" and "conduct tending to hamper the work" of the DAR.

The DAR's national board voted to reprimand Tiberio and another woman who did not join the suit and then suspended the reprimands.

DAR lawyer Stuart Philip Ross termed the lawsuit "another effort by a disgruntled member of the society to hamper the work of the society . . . . It is obvious that Mrs. Tiberio intends to use all means, including the filing of a baseless lawusit, to keep alive her vendetta against [DAR President Sarah] King and the society."

The disciplinary proceedings stemmed from an April 1984 news conference in which the women announced an effort to impeach King and criticized a proposed bylaw amendment that would have required applicants not only to prove a Revolutionary War connection, but also to show that their descent was "legitimate."

The amendment would have had the effect of barring most blacks from membership because slaves generally were not permitted to enter into legally binding contracts, including marriage, Tiberio said.

Tiberio's suit seeks $3 million in damages, expungement of the reprimand and a public apology.