Okay, it's definitely interrupted filament feed. I had this problem the other day and it turned out to be dust clogging my extruded nozzle; canned air did the trick. That said, it sounds like you've already eliminated that.

While upping the heat improves filament flow, do be careful. While no two hot ends will give the same reading at a given temp, I set my MakerGear M2 to 212C for PLA. Not saying you should use that number at ALL as you've got a different rig.

In any event, you're doing the right thing by gradually upping the temp in 5 degree steps.