The battered natural gas pricing bill suffered another serious blow yesterday when two House members, who had supported an agreement reached in May, backed off and refused to sign the conference report.

Rep. Joe D. Waggonner (D-La.) repudiated the agreement to end price controls on newly discovered gas by 1985 after studying the technical language. He said he felt it did not conform with some aspects of the May agreement, and did not do enough to help producers. Rep. Henry S. Reues (D-Wis.), on other hand, decided it was so inflationary and put such a burden on consumers that he could not support it.

Since House conferees had approved the May agreement by a vote of 13 to 12, these defections leave the House side short of the majority which must sign a conference report to permit it to be filed in House and Senate for final approval.

Yesterday afternoon, as the House prepared to quit for three weeks, Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) called to his office Reps. James C. Corman (D-Calif.) and Charles B. Rangel (D-N.Y.), both of whom voted against the May agreement and oppose the conference report.

O'Neill asked them to sign the report to give Congress a chance to vote on it. They evidently refused, but finally agreed to meet with president Carter last night to let him make a final pitch for their support.

"I don't know what he can say," Rangel said.

Ten of the needed 13 House conferees have signed the conference report. But Rep. Charles Wilson (D-Tex.), said yesterday that if they get 12 he will sign up to make 13. "I would not be the one to prevent the House from voting on a national energy policy," Wilson said.

Wilson said he was inclined to sign the report anyway because he did not share Waggoner's view that the written document made changes in the May agreement.

The House conferees agreed Wednesday to make changes, intended to satisfy producing states such as Waggoner's, with provisions limiting the reach of a recent Supreme Court decision some feared might divert much intrastate gas into interstate markets.

Waggonner conceded that the conference report had been changed this week to "move in our direction," but said the movement wasn't enough. Waggonner defected after several meetings with Sen. Russell B. Long (D-La.), chairman of the Senate finance Committee, which has demolished Carter's energy taxes, the other major part of his energy bill.

House managers of the gas bill had hoped to get the necessary 13 signatures by yesterday because of the start of the House recess. They fear there won't be time to get it past a Senate filibuster if the start of debate is delayed until after Labor Day.

Eight of the needed nine senators have signed the conference report. Backers hope Sen. James A. McClure (R-Idaho.), will be the ninth.

The fight over continued price controls or deregulation of natural gas involves billions of dollars, and has eluded congressional solution since 1954, when the Supreme Court upheld the power of the government to regulate the wellhead price paid for gas piped across state lines.

A major part of the top priority energy bill Carter sent Congress 16 months ago was a provision to continue price controls on gas at higher levels than now and extend regulation to cover the intrastate market.The House approved his program, but the Senate voted to deregulate after two years.

House-Senate conferees have been trying to reach a compromise for eight months.