you have not mentioned taking off the faceplate assembly and oiling the needlebar and presser bar. It is a tricky job and getting it back together is not fun. There is a connecting rod that is not tied down and is tricky to align when you put it back together. but if it is noisy, it would probably be a good idea to open and oil. Have a camera ready. I used tweezers to thread min the first time or two.