Thanks for the tip the extruder wheels were dirty from all the grinding but there is a tensioning spring and i have it quite loose because i had an issue with PETG because i have my printer in enclosure and with bed at 80C in enclosure was so warm that my filament which is inside the enclosure as well was so soft that extruder squash it a little bit and it git stuck inside that longer ptfe tube which is between extruder and hotend

I did have nozzle cleaned but my ptfe tube is totally melted and i lost the spare so i flipped it and it did helped a lot i have managed to print something without a fail but still only at high temperature 235C so i had a lot of strings so tomorow i will try to find the replacement i hope it will fix it

just came to my mind that I can try to check ptfe tube that goes to hotend I know those are a bit sensitive to heat even tho in Prusa Mini the tube shouldn’t be in a melting zone but mine is very old. It is the one that my printer comes with so maybe I should replace it. I will update you guys if that is the case.

Yes, I have tried that but it didn’t help then I tried to burn away everything in a nozzle with a flame so the nozzle was very clean and I think it helped a little but after a few minutes of printing PLA, I still heard grinding of filament.

Yes PETG is printing just fine. I have switched to PETG also from Prusament to finish the print which bugs me because I like the colour of the PLA I have better for this one.