The sun is barely above the horizon, heading toward 100 degrees, and over eggs and biscuits, Rep. Charles W. Stenholm is explaining to an audience of oil and gas producers "one of the toughest votes" he has ever cast in Congress: the one against President Reagan's $98.3 billion tax bill.

Stenholm, a leader of the Democratic "boll weevils" in the House, runs through various explanations, the last a startling admission from someone who has fought for balancing the budget since he came to Congress in 1979.

"When you have an economy as sick as we have," he says, "how much difference . . . would another $20 billion in deficits really make?"

Only Stenholm seems to realize the heresy that has slipped from his lips, and he recovers quickly. "About this time, somebody ought to throw something at me, talking about another $20 billion in deficits," he says with a laugh.

But no one in the audience so much as drops a fork. The tax bill that created so much political confusion in Congress appears to have generated a similarly confusing reaction in Stenholm's enormous congressional district in west central Texas.

In the audience on this hot summer morning is Glen Michel, executive director of the West Central Texas Oil and Gas Association. Michel opposed the tax bill, but when asked about Reagan's support of the measure, he replies with a shrug, "Reagan's in trouble. We know that. He may have asked for too much in tax cuts originally, but give him credit. He's trying to turn it around."

Turning the economy around is as important to the people in Stenholm's district as to those in Michigan or Alabama. Elsewhere in the country, Texas may still appear to be an economic powerhouse, but the recession has cut deep in Texas' 17th Congressional District.

From a speeding automobile, the cotton looks healthy and the oil wells productive. But that is deceptive.

The worldwide oil glut has cut domestic drilling by 45 percent since the end of last year. Abilene's largest employer, an oil-field pipe company, recently filed for bankruptcy, while an oil-field storage tank company in a nearby town has laid off a large part of its work force.

The farm economy here is perhaps in even worse shape. By mid-morning, Stenholm is heading west from Abilene for a field day sponsored by a cotton seed company in Loraine. Earlier this summer, rain and hail destroyed 90 percent of the cotton crop in the surrounding county, and today, many farmers face financial disaster.

But Stenholm has not come to Loraine to coddle his constituents. Standing in a huge shed, he tells about 150 farmers that they "are at the lick log" in finding a solution to the problems facing agriculture, and criticizes them -- and the administration -- for failing to acknowledge that "there ain't no such thing as a free market" in agriculture.

The tax bill is what preoccupies him, and when he talks about his split with Reagan on it, he is more tentative -- even though his constituents are clearly of mixed mind.

Lemoine Unger, cutting into a piece of watermelon, says he is still an admirer of the president, though not especially enamored of the tax increase. For him, "The thing to remember about this tax bill is that it doesn't really affect me."

The message from this district is that neither Reagan nor Stenholm apparently will pay for their opposing positions, if the economy responds.

But if it doesn't, then a throw-away line, given in the shadow of the shed in Loraine, may be more telling. "I take my responsibilities seriously," Stenholm told the farmers, joking that he is unopposed for reelection. "But I also take seriously the bumper sticker I see around here that says, 'Don't reelect anybody.' "