TWhiting33

Hi, I'm using an Ultimaker 2+ and am trying a 0.25 nozzle for the first time with PLA material. It keeps failing at about an hour into a 20 hour print. At first, the raft wasn't sticking, and there were pock marks on the top surface. After a couple failed attempts, I updated the firmware on the machine, slowed down the first layer, and calibrated the nozzle slightly closer to the build plate. This helped for the first hour (the first layers were beautiful) and then more pock marks on top, and the material stopped feeding out. Any suggestions on settings I might be missing? Do I need to run this nozzle slow for the whole build? Thanks, Teresa