McCoy, who had 30 carries, found the end zone on a 2-yard run in the first quarter to put the Eagles up 14-0. He added a 13-yard TD scamper in the fourth to wrap up the scoring for Philadelphia (3-4).
Michael Vick completed 21-of-28 passes for 279 yards and two touchdowns as the Eagles rolled up 495 yards of total offense.
Brent Celek collected seven passes for 94 yards and a score for Philadelphia, which won its second straight following a four-game losing streak. The Eagles have now pulled even with Dallas and Washington in the NFC East.
Tony Romo completed 18-of-35 pass attempts for 203 yards, one TD and an interception for the Cowboys (3-4).