DAMASCUS, Syria (AP) _ Saudi Arabia's foreign minister looked for a way to revive a stalled Lebanese peace conference Thursday by discussing guarantees for a Syrian pullout in a meeting with President Hafez Assad, sources said.

In Beirut, a key aide to Christian leader Gen. Michel Aoun said Christian Lebanese legislators negotiating with their Moslem counterparts in Taif, Saudi Arabia, should come home if they reach no agreement by Friday.

But one Christian lawmaker said even if the meeting in Damascus made no headway, the Christian delegation had no plans to leave the 3-week-old talks aimed at ending Lebanon's 14-year civil war.

An official source in the Syrian capital said the Saudi minister, Prince Saud al-Faisal, who arrived Wednesday, met with Assad and gave him a letter from King Fahd.

It was not yet known whether Syria had accepted to give a guarantee that the 40,000 Syrian troops will be pulled out of Lebanon completely, a key demand of the Christian side at the Lebanese parliament meeting in the Saudi resort of Taif.

Presidential spokesman Jibrane Kourieh said Syrian Vice President Abdul- Halim Khaddam and Foreign Minister Farouk al-Sharaa also attended the meeting.

In Taif, conference sources said the Saudi government was trying to work out a formula to meet demands by Christian legislators for guarantees that Syrian troops withdraw from Lebanon according to a specific timetable.

The Syrian forces have remained in Lebanon since 1976 under an Arab League peacekeeping mandate and have become the main power brokers in the country.

The Christians led by Aoun charge Damascus violated its mandate by siding with the Moslems in the civil war and have declared a ''war of liberation'' against the Syrians.

In Beirut, Farouk Abillama, secretary general of Aoun's foreign ministry and one of the general's closest advisers, said after a meeting with the Christian leader: ''It is not permissible that the Syrian army remains (in Lebanon).''

''We demand clear guarantees that the Syrians will withdraw,'' Abillama said.

He said the Maronites have agreed to the reforms, ''so let them give us something in return.'' Abillama was referring to reforms designed to give Moslems more power in Lebanon's currently Christian-dominated political system.

The parliamentary deputies meeting in Taif ''should return in 24 hours if they fail to reach agreement,'' he said at midday.

But in Taif, Maronite parliament member Pierre Dakkash said the Christian deputies will not withdraw even if Prince Saud brings back from Damascus a negative reply to demands for troop pullout guarantees.

The 63 members of Parliament have been meeting in Taif under the auspices of the Arab League since Sept. 30.

Conference sources said Prince Saud has advised the Christians to accept that the reassurances they seek be contained in addenda to the accord, not in its basic provisions. They said he asked the Christians for flexibility on the issue, before taking an outline of their requests to Damascus.

The political reforms are outlined in a draft charter prepared by the mediating committee of Saudi Arabia, Morocco and Algeria, which envisaged a maximum two-year phased withdrawal of the Syrians from Beirut and its environs.

The Syrian troops would be deployed in Lebanon's eastern Bekaa Valley for an indefinite period until a strong central government is established in Beirut and it signs a security pact with Damascus.

Aoun rejected the indefinite stay and insisted the Syrian withdrawal start as soon a draft charter for national reconciliation is ratified by a parliamentary session in Beirut.