Aah, I just had this problem myself. You say you changed the needle? Check the alignment of it. The eye should be straight with the front of your foot. Loosen your screw that holds the needle in & I use a corsage pin to hold the needle & adjust. Just turn it in small increments til the loops go away. Once you get it aligned, take a magic marker & mark your foot for the appropriate spot for future reference. By the way, some machines like their needles just a tad off center. Maybe yours does too.