Things are not going well for the once-invincible Dallas Cowboys.

Two weeks ago, they were coasting with an 8-0 record. The only unanswered question seemed to be who they beat up in the Super Bowl.

Then Dallas lost to the resurgent St. Louis Cardinals and on Sunday the resurgent Pittsburgh Steelers handed the Cowboys their second straight defeat.

Coach Tom Landry is obviously concerned, as are many of his players.

"We're in trouble. There's no way around it," said defensive end Harvey Martin.

Martin is probably right, especially if the Washington Redskins beat the Cowboys on Sunday at RFK Stadium.

Dallas leads the NFC East with an 8-2 record, one game ahead of St. Louis and two ahead of Washington.

"We need something to get us going again," Landry said today. "If us go up there and beat Washington in its back yard, it'll give us a big psychological lift."

The fact that Washington is struggling is no reason for Landry to think his team will have an easy time. Landry has a cold that swelled both his eyes and made him unable to watch the Redskins' 10-9 victory over Green Bay on Monday night, but he said he listened to it and "enjoyed it until the end."

"Washington has had troubles this season, mainly because of a loat of injuries," Landry said. "But when you go into a given ball game the outcome depends on how well the people you have perform in that particular game. What went on before doesn't have that much of an effect. It will be a tough game Sunday because Washington has to win to stay in the playoffs. It'll be a fight."

The Cowboys have lacked zip the last couple of weeks and it has shown in their offense, defense and special teams.

""We have to get back playing with the same intensity we had at the start of the season," said safety Cliff Harris. . "We're got the talent, but everybody's got talent in this league. We're got to start putting out more."

Middle linebacker Bob Breuning said, "Maybe we just aren't tough enough."

Landry has other thoughts. "The season is so long that teams play at up and down levels and if you're on a down like we have been the last two weeks you're in trouble."

Landry feels that the fact that the Cowboys won their first eight games may have had them thinking they could win them all merely by showing up.

"If you're bragged on enough, you have to start believing it," he said. "It was almost ridiculous, though, for any, one to think we could have gone undefeated.

"When Miami did it they were a seasoned team. We are still very young."

Landry is concerned about the play of outside linebacker Tom Henderson. One of the most talented young defensive players in the league, the flamboyant Henderson has been dormant lately, "so-so" in Landry's words.

"He just isn't making the same exciting plays he made earlier in the season. It would sure help us if he would start making them again," Landry said.

There is no quicker defense in the league than Dallas and because it is so sound overall, the Cowboys do little blitzing, only 5 per cent of the time. Its scouting reports say the Redskins, in contrast, blitz 17 per cent of the time, more than any other team the Cowboys play. In the first Redskin-Cowboy game, won by Dallas 34-16, Washington blitzed 25 per cent of the time.

Neither Landry nor any of the Cowboys will say if he prefers to face Bill Kilmer or Joe Theisman at quarterback. There has been speculation that Kilmer would start against Dallas to try and give the Redskins a psychological edge. Landry is not expecting that. "Obviously George (Allen) feels Theismann is better for his offense than Billy, but I don't know."

Landry said that Theismann likes to pass from a rollout and is a good runner, which means his team has to prepare a little differently for him than it would for Kilmer.

Rookie running back Tony Dorsett had his first start of the season at Pittsburgh last week and gained 73 yards in 17 carries. He also scored on a 13-yard run.

"He ran well and he ran hard," Landry said, "and he'll start again this week against Washington."

Dorsett is seventh in the NFC in rushing with 595 yards. He is averaging 4.6 yards a carry and has scored eight of the team's 15 rushing touchdowns.

The only Cowboy not expected to play is tackle Rayfield Wright, out with an injured Knee.

Another Dallas streak ended today. As a feature of the Cowboy weekly news conferences, there is a phone interview with the coach of the upcoming opponent. They were 10 for 10 on getting coaches to consent. Today Allen would not.

"I don't really blame him," said Landry. "He must have a lot of things on his mind."