I had problems once with my machine that it took me a long time to figure out. I threaded, rethreaded, changed the needle, cleaned, cleaned and oiled. Finally since everything else had been done, I changed the thread. Problem went away and (knock wood) hasn't resurfaced. Every once in awhile you can get a bad spool. It was a quality thread, and the only mfg. I use. I emailed the mfg and they sent me a new one. Great customer service.
Agree on lowering the presser foot. And, slow down. I don't have my machine set to full speed and that helps a lot.