Try an 80/12 Microtex needle. I got that tip from my service lady. My machine is a Pfaff and Pfaffs prefer 80/12 needles per my service lady. Found this to be true, I have way fewer issues with the 80/12 needle. I also started using Aurifil 50 wt. 95% time.
If I have issues I can pretty much chalk it up to operator error.