I have that machine too and I found it to be a piece of junk. It broke 3 months after I got and it cost $135 to get it fixed. It broke again 5 months later and it was doing just what yours seems to be doing. Slowing slowly or not sewing at all. I gave up on it. I am NOT going to fix it again. Did you get it off of Amazon? I did and have since heard from many sources that they are not good machines.