* Vote scheduled at 4:45 p.m. ET
* Indexes on track for biggest weekly decline of the year
* Micron jumps after rev, profit forecasts beat estimates
* Indexes up: Dow 0.04 pct, S&P 0.2 pct, Nasdaq 0.53 pct (Updates to early afternoon)
By Tanya Agrawal
March 24 (Reuters) - U.S. stocks pared gains in choppy trading on Friday as investors braced for the outcome of a vote on a healthcare bill that is seen as a test of President Donald Trump's ability to pass his legislative agenda through Congress.
Republican lawmakers struggled to overcome differences over the bill after Trump walked away from negotiations, telling them to pass the bill on Friday or keep Obamacare in place.
The back-and-forth over the bill has led to some of the choppiest trading Wall Street has seen since Trump's election in November and has set its main indexes on course for their worst weekly decline of the year.
Investors had worried that a failure of the legislation would damage prospects for Trump's pro-growth agenda, including tax reform and stimulus. Earlier this week, U.S. stocks posted their biggest daily drop since the election on these concerns.
Some of that concern appeared to be ebbing on Friday ahead of the scheduled vote in the House, with some analysts and investors seeing a failure of the bill as a catalyst to bring forward action on tax reform in particular.
Trump warned lawmakers late Thursday that he was prepared to do just that: move on.
"I think at this point it's really a 'put-up or shut-up' moment for the Trump administration and what he's done is pretty bold," said Brad McMillan, chief investment officer at Commonwealth Financial Network.
"This is a kind of decision that the market wants to see Trump make and they're giving him the benefit of the doubt on it. One way or the other it clears the deck for tax reform. Trump may very well loose the battle but win the war."
The S&P has risen about 10 percent since Trump's election as U.S. president on Nov. 8.
At 12:31 p.m. ET (1631 GMT), the Dow Jones Industrial Average was up 8.08 points, or 0.04 percent, at 20,664.66, the S&P 500 was up 5.54 points, or 0.2 percent, at 2,351.5 and the Nasdaq Composite was up 31.05 points, or 0.53 percent, at 5,848.74.
Eight of the 11 major S&P sectors were higher, with the technology index's 0.68 percent rise leading the gainers.
Micron Technology jumped 8.8 percent to $28.78, a day after the chipmaker's current-quarter revenue and profit forecasts beat expectations. The stock was the biggest percentage gainer on the S&P.
Goldman Sachs was down 1.1 percent at $229.38 and was the biggest drag on the Dow.
Data on Friday showed new orders for key U.S.-made capital goods unexpectedly fell in February, but shipments surged.
The Commerce Department said non-defense capital goods orders excluding aircraft, a closely watched proxy for business spending plans, dipped 0.1 percent last month after rising 0.1 percent in January.
GameStop tumbled 12.3 percent to $21.05 after the company's full-year profit forecast fell far below estimates.
Advancing issues outnumbered decliners on the NYSE by 1,883 to 945. On the Nasdaq, 1,816 issues rose and 873 fell.
The S&P 500 index showed 19 new 52-week highs and one new low, while the Nasdaq recorded 52 new highs and 23 new lows. (Reporting by Tanya Agrawal in Bengaluru; Editing by Anil D'Silva)