Holes and pockmarks in print walls

[PLAyer_uno]

Hello, I'm new to 3d printing and this is my first post here. Recently bought an old Ender 3 with 1 partially used roll and 1 new packaged rool of Sunloo PLA+. Used what remained of the first spool to train myself to calibrate the printer and was very happy with the prints I was getting - they were surprisingly good, for a newbie. When the first roll ran out and I decided to change the original white bowden tube for a new Capricorn one and also fit new higher quality connectors on the extruder and hot end. Also changed to a new nozzle. That's I started getting holes or 'pockmarks' in the walls of my prints. For example, see photo of a slicer flow calibration 'cube' I printed today, where there's lots of holes, where before I'd print the same part and the walls had no holes at all. This is happening with a new filament roll, right out of a sealed bag - so doubtful the problem is moisture in the filament.Don't think the problem low slicer flow, as the walls of the 'cube' should be 0.4mm thick, but with a vernier caliper they measure 0.46 to 0.5 - so seems flow is too high by 15% to 20%.Also don't think the issue is bed adhesion, as the part sticks quite well to the bed until it's cooled down (and it's the same bed, same filament, etc)This is what I've tried so far to try to fix it:- Cleaned the bed with alcohol before every print.- Levelled the bed (several times, it's as good as level as can be)- Hot-pulled filament and inserted needle through nozzle - came out clean, no obvious clogging- Enabled thin walls in Cura- Increasing nozzle temperature to up to 210CAny advice will be much appreciated!

[Bikeracer2020]

Looks like some under extrusion there.

Possibly a gap between the end of the bowden tube and the new nozzle, the bowden tube needs cutting square and butting up to the nozzle to prevent melted filament escaping above the nozzle.

An all metal hotend conversion helps to prevent this because the bowden tube ends before the heat break.