Btw, in the 4-way matchup, Trump is at 2% among black voters in this poll, behind both Johnson and Stein. Harry Enten has a story here:
http://fivethirtyeight.com/features/trump-is-in-fourth-place-among-black-voters/in which he averages together the latest ABC, NBC, Fox, and Marist polls, and finds that among black voters, the average is:
Clinton 86%
Stein 5%
Johnson 4%
Trump 2%
So yes, Trump being in fourth place among black voters appears to not just be a fluke from one or two polls. It’s something that we’re seeing pretty consistently from different pollsters.
There’s also this: