Extruder calibration

Hi. Yesterday I noticed my prints coming out slightly under extruded, I’ve checked and it seems that the filament path is clean and the extruder does not tick or make any noises during print which would suggest lost steps or the wheel letting go. I’ve checked the extruder driver’s reference voltage and it’s right at 1.05V.

For my other printer I’ve made a little piece of PTFE tube which is exactly 100mm long and after writing a gcode that extrudes 100mm (please unlock axes movement from the LCD if you ever update Marlin) I’ve seen only about 97mm coming out. Right now I’m printing at 103% flow to see if this will compensate but it should not be required to do so. Is this normal, can anyone else confirm this is also the case for other printers?

There is one screw that goes through the lever to load the filament.
this one you want to leave a little loose

You can change steps/mm in Menu->Control->Motion and store it with M500 or Menu->Control->Store Settings. I never needed to do it, but I think it is very common that one might check or change this settings.

Thank You guys for the suggestions. I’m sure the screw on the extruder is loose, I’ve taken it apart already, as I have the entire printer. I totally forgot about the steps per mm calibration in settings, I will adjust that instead of the flow.