* Apple rallies, lifting S&P 500 and Nasdaq
* Weakness in Coca-Cola limits Dow's advance
* S&P 500 back above 14-day moving average
* Indexes up: Dow 0.9 pct, S&P 1.4 pct, Nasdaq 1.7 pct
NEW YORK, Oct 21 (Reuters) - U.S. stocks rallied on Tuesday, with the S&P 500 on track for a fourth straight session of gains boosted by strong corporate results, including Apple's.
The S&P 500 and Nasdaq were both up more than 1 percent while the Dow's gains were limited by a selloff in Coca-Cola shares.
The S&P 500 has gained more than 6 percent from its session low last Wednesday, when the benchmark was down nearly 10 percent from its intraday record. The index is on track to close above its 14-day moving average for the first time since Sept. 24 and was also trading above its 200-day average.
At 1:16 p.m. EDT (1716 GMT) the Dow Jones industrial average rose 149.5 points, or 0.91 percent, to 16,549.17, the S&P 500 gained 26.76 points, or 1.41 percent, to 1,930.77 and the Nasdaq Composite added 72.02 points, or 1.67 percent, to 4,388.09.
Apple Inc rose 2.4 percent to $102.18 a day after revenue topped expectations, helped by strong iPhone sales. It also gave a strong outlook for the holiday quarter.
The largest percentage gainer and decliner on the S&P 500 were both related to earnings. Waters Corp rose 9.3 percent after reporting early Tuesday, while Coca-Cola fell 6.2 percent in its biggest one-day decline since October 2008.
The largest percentage gainer on the Nasdaq 100 was Illumina Inc, which rose 8.6 percent a day after it said it expects full year adjusted net profit to be well above Wall Street's expectations, while the largest decliner was Mattel , down just 0.2 percent.
While earnings have largely come in strong so far this quarter, concerns continue to swirl over the pace of global economic growth. China's gross domestic product grew 7.3 percent in the third quarter, the slowest pace since the first quarter of 2009.
U.S. existing home sales rose 2.4 percent in September, above expectations, hitting their highest level in a year.
Advancing issues outnumbered declining ones on the NYSE by 2,418 to 613, for a 3.94-to-1 ratio on the upside; on the Nasdaq, 1,803 issues rose and 797 fell for a 2.26-to-1 ratio favoring advancers.
The benchmark S&P 500 index was posting 17 new 52-week highs and 1 new low; the Nasdaq Composite was recording 34 new highs and 22 new lows. (Reporting by Rodrigo Campos; Editing by Nick Zieminski)