Yizhou, when the person before you says to do something first, then you post and say to do something else first all it does is leads to confusion.

Pay attention to what others post then say things like in addition to what whoever said you will want to also try or check this.

I know you know XYZ but your help needs to merge with the help others have already offered and not seem to counter it.

Keep in mind that unlike you and I most people are now buying these XYZ printers to get in to 3D printing at a very low cost but have very little knowledge about 3d printing and much less about the printer so avoiding confusion is important when trying to help them.

I would do what you suggested if question is about Da vinci 1.0 not Jr.
I'm not interested in counter anyone but I do want to express the difference in priority in this case, although I do understand I may be wrong.

First, try to manually push the filament though. if it is still slow, you have clogged hotend throat or nozzle. if manually push smooth, trim you PFTE tube from both end, and check if you step motor gear is fixed to step motor axis. there is a hex screw on the gear that may become loose.

Yizhou, when the person before you says to do something first, then you post and say to do something else first all it does is leads to confusion.

Pay attention to what others post then say things like in addition to what whoever said you will want to also try or check this.

I know you know XYZ but your help needs to merge with the help others have already offered and not seem to counter it.

Keep in mind that unlike you and I most people are now buying these XYZ printers to get in to 3D printing at a very low cost but have very little knowledge about 3d printing and much less about the printer so avoiding confusion is important when trying to help them.

Thanks