The House Committee on Standards of Official Conduct has sent a broad-ranging questionnaire to House members asking them to spell out in detail any unauthorized changes they have ever discovered or have been told about in any official transcripts or proceedings.

A covering letter, dated July 29 and signed by Chairman Louis Stokes (D-Ohio) and the senior Republican on the panel, Floyd D. Spence of South Carolina, said the questionnaire arose out of the committee's investigation into who altered the transcripts of an environmental hearing July 21-22, 1982, in ways that made Republican participants look foolish.

So far, the committee has not released names of any suspects. But in the letter sent with the questionnaire the panel said its investigation is not limited to the 1982 hearings, but also has the broader purpose of trying to determine whether transcript distortions are widespread in the House.

The ethics committee said it wants members to list any instances in which a transcript of a hearing, committee meeting, floor statement or any other official proceeding was changed without authorization.

The questionnaire must be returned by Sept. 15. It was sent to all current House members who also served in the last Congress and to some staff members.

In another action, the ethics panel turned down a request by Reps. Larry Winn Jr. (R-Kan.), Robert S. Walker (R-Pa.) and Joe Skeen (R-N.M.) for an investigation of a hearing conducted July 11 in Tennessee by Reps. Albert Gore Jr. (D-Tenn.) and Marilyn Lloyd (D-Tenn.). The panel said their complaint was not "sufficiently substantial" to warrant action.

The three Republicans charged that Gore and Lloyd violated House Science Committee rules by holding a hearing without a Republican member present. The rules say two members must be present, including at least one minority member, and the chairman must be a majority member.

The ethics committee said that the action was at most a technical violation of Science Committee rules and not an ethical breach worthy of an ethics committee probe.

Moreover, it said the usual practice in the Science Committee had been, in effect, to the treat the rules as a guideline.

It cited a letter from Science Committee Chairman Don Fuqua (D-Fla.) listing 350 instances in which only one member of the committee was present, or members of only one party, or in which a Republican chaired the meeting.

In one case, on July 30, 1982, Skeen, a minority member, chaired a meeting with no Democrat present, Fuqua said, adding that Skeen was quoted in the hearing transcript as saying, "Fortunately, the rules of the House permit a hearing to go on as long as there are two members of either party."

A Skeen aide said last week that the July 30 hearing was held as a "briefing" and was elevated later to the status of a hearing.