I've been having some difficulty underextrusion on my new all-metal hotend. I've set my retraction distance to 1.5mm (1.0 leaves strings), but on regular PLA I'm getting occasional layers that don't print very well (particularly if there's a lot of stopping and starting), and glitter PLA is an absolute disaster.

Any suggestions for getting this to work? Does glitter PLA just not get along with all-metal hotends? Is it possible that there's hardened PLA up past the heat break that things are catching on, and if so, how can I clean that out (I've been using cleaning filament already, and it doesn't seem to be solving the issue)?

FIXED: Increasing my flow rate fixed this. I started at 110, which was a bit better, then went to 120, which was a bigger improvement, and at 125 the first layer printed perfectly.

EDIT: This was a symptom of my extruder needing to be tightened and recalibrated. It now prints perfectly with a flow rate of 100%.