A widening trade gap, a more sluggish consumer and softer business spending bit into fourth-quarter growth, and economists now expect that the economy grew at about 2.3 percent in the final quarter of 2018.

On top of that, first-quarter growth is looking even weaker, at less than 2 percent, and the economy in the two quarters appears to have fallen back to the pace it was at before President Donald Trump entered the White House. That follows growth above 3 percent in the third quarter.

Fourth-quarter GDP is released Thursday at 8:30 a.m. ET.

If the number matches the Refinitiv consensus forecast for the fourth quarter, GDP growth for all of 2018 will be 2.9 percent, slightly less than the 3 percent targeted by the Trump administration. Economists are expecting that some of the factors affecting it are transitory and related to the government shutdown or trade conflicts.

Economists were encouraged by a sharp rebound in February consumer confidence Tuesday, suggesting that the consumer may be now looking past the shutdown and the stock market sell off in December.

"The bad news is with the tax reform bill, the Republicans were promising this would lead to a permanent lift in business investment which would lead to productivity growth in the U.S. which would let us grow at 3 to 4 percent, and that really hasn't taken shape," said Scott Anderson, chief economist at Bank of the West. "This hope of a permanent lift in productivity doesn't seem to be playing out, and therefore we're going to go back down pretty quickly to where we were, but now we're going to be be running trillion-plus deficits on top of it."

Anderson said he cut his forecast for fourth quarter growth to 2 percent Wednesday after trade data showed a record deficit in goods in December of $79.5 billion, up 10 percent from a year ago. The surprise drop in December retail sales, reported earlier in the month, also added to a reduction in consumption to a slower pace of about 2.5 percent.

"Residential investment, or housing, is down around 5 percent or so, and there's lackluster equipment spending that probably grew a bit below four percent. Structural investment, or commercial real estate is down 1 percent, and consumer spending at 2.5 percent is a big come down from the third quarter when we were at 3.5 percent," he said. "The trade numbers suggest we could see negative or flat export growth in the fourth quarter."

Anderson said his first quarter growth forecast is just 1.5 percent.

"It's going to be really hard to get that 3 percent growth rate this year. The fiscal stimulus is probably going to add half as much as it did last year. You're just not going to get as much support for consumer and business spending as you did in 2018. We do expect slower growth around the world in 2019," Anderson said.

The CNBC/Moody's Analytics Rapid Update consensus for fourth quarter growth estimates was 2.3 percent, and the forecast for first quarter was an average 1.8 percent.

Citigroup was among the firms that trimmed fourth quarter growth forecasts Wednesday, shaving off 0.3 percentage points, to 2.2 percent.

"This is one of the prints that just has a lot of question marks all over it, especially with the December retail sales data which seemed out of sync," said Shawn Snyder, head of investment strategy at Citi Personal Wealth Management. "We're trying to react to the December retail sales data, and we're already seeing consumer confidence pickup in February."

"Some of the other stuff like the trade data, you could overlook just because some of it is related to the trade war. You want to separate the fundamentals from some of these transitory effects," Snyder said.

Anderson said the a bright spot remains the labor market, which has shown solid growth. "The Fed is saying they're seeing higher wage growth. Maybe there is still some good news there," he said. "The wild card is the consumer. Will they come back?...Maybe the consumer will come back in the second quarter. Maybe we're too pessimistic on the consumer."