Your flight leaves at 8:55am. What time do you want to arrive at EWR? 2 hours in advance? If you want to be driven door-to-door, take car service. Don't take a taxi because it will be more expensive. We have a thread about car service in this forum so you can decide for yourself which you want to take.
http://www.flyertalk.com/forum/new-y...-services.html
I like Dial 7 or Carmel.
You don't want to take a taxi because you'll have to pay ROUNDTRIP for that NYC taxi to return to Manhattan. NYC taxis aren't allowed to pick up fares at EWR.
So you're on 14th Street....on the west side? East Side? Well, whichever, allow an hour.