Carter administration officials, caught off guard and admittedly puzzled by Egyptian President Anwar Sadat's abrupt turnabout on the Palestinian autonomy talks, said yesterday they do not believe the Egyptian move will cause any serious delays in the Middle East peace negotiations.

Less than 24 hours after Sadat announced that in deference to a personal appeal from President Carter he would resume the stalled autonomy talks, Egypt did a U-turn and rejected the idea of continuing negotiations.

U.S. officials said privately that the announced Egyptian rationale for the move -- an Israeli parliamentary resolution declaring that Jerusalem is the eternal capital of the Jewish state -- does not appear to be the real reason behind Sadat's change of course. But, the officials added, they were unable to guage immediately what prompted the switch.

"The only thing we know is that the Egyptians, for reasons we can't yet get specified, decided that it's in their tactical interest to keep the talks in suspension for the moment," one U.S. source involved in the negotiations said.

He added that Washington has started urgent consultations with Egypt and Israel in an attempt to unravel the latest snarl and said the United States hopes to have a clearer picture, "probably within the next 24 hours."

The initial feeling here, U.S. sources said, is that Sadat has no intention of scuttling the negotiations. Instead, they continued, Washington's belief is that he either is resorting to a shock tactic aimed at speeding up the sluggish pace of the negotiations or has felt obliged to put the talks on hold temporarily because of some unexpected problem within his government.

If either of those suppositions is correct, the sources said, the expectation here is that the talks can be put back on track in the relatively near future with only minimal delays. However, they cautioned, Washington won't really know if it has a new crisis brewing until the U.S. ambassador in Cairo, Alfred L. Atherton, is able to obtain more information about what Sadat has in mind.

Despite commitments to intensified negotiations made by Sadat and Israeli Prime Minister Menachem Begin during separate meetings with Carter last month, it has become clear that the negotiations will not meet their May 26 target date for an agreement on a self-government system for the Palestinian inhabitants of Israeli-occupied territories.

After the last round of talks in Israel failed to make progress, Sadat said he wanted a temporary halt. On Wednesday, though, during a long speech outlining a reshuffling of the Egyptian government, Sadat announced that Carter had called him a day earlier and that, after a long talk, they had agreed that the talks should be resumed.

U.S. sources said that, in the wake of that announcement, Carter's special mediator in the autonomy talks, Sol M. Linowitz, had been planning yesterday to begin arrangements for the next round in Cairo. The sources said Linowitz tentatively had hoped for a resumption around May 26, but they added that this timetable could now be set back by the latest Egyptian move.

In announcing the suspension, Egypt angrily cited the action of Israel's parliament, the Knesset, which on Wednesday passed a resolution reaffirming the longstanding Israeli position that Jerusalem should remain an undivided city and the capital of Israel.

U.S. sources pointed out, however, that the resolution was a nonbinding move comparable to a sense-of-Congress resolution in this country, that it broke no new ground in terms of Israel's negotiating position, and that the Egyptians were aware of these facts.

As a result, the sources said, an Egyptian rejection of continued talks because of the resolution was either an overreaction or, more likely, an excuse to cover some other reason for delay.

In addition to the inquiries, being pursued by Atherton in Cairo, the sources said, Linowitz talked yesterday with the Israeli ambassador here, Ephraim Evron.