Ender 3 pro extruder problem

Hello there,I own Ender 3 pro for half a year right now. As it has been forseen in the internet default extruder did break and i had to replace it. There is a problem tho, cause since then it started to lose stepps. I did some resarch and i am sure that my nozzle is not jammed (I performed cold pull many times). I did change nozzle too. I level my bed using paper sheet, but i am sure its not too close to the bed. I figured out that if i rise temperature and lower speed of printing, skipping gets rarer, but it happens from time to time. I also can tell that it was happening even with old extruder, but it was very rare and i didnt know what it was back then. Probably the problem lies in new extruder. Maybe the spring has too much tension, but i dont have any tools to lower it. I tryied to put old string in new extruder but it didnt work either. So now im looking for solution. I can print in like 50% speed, but it is not comfortable. I thought about maybe rising extruder's stepper current, but i dont know how to do this, if i even can do it or if it is safe.