Read this post by me. Try each step as i explain what to do.
Also make sure you really use a good bit of ipa on the carbon rods. Make sure the toolhead moves smoothly on the x axis. Then continue with the steps in the post below. Clean your z screws also. Especially if you went thru a stringing event on a previous project.
https://forum.bambulab.com/t/horrible-z-lines-what-could-it-be/57793/4?u=barryg41
HTHelps!