Pfaff expression 2.0 works the same. I spend lots of hours with the thread tension and it don;t give me a good stitch. the needle threed ends up making large irregular loops .

I have a 2.0 and I had a problem similar to yours, I think. I took it to my shop. I watched her re thread my machine. I was not threading the bobbin properly! After you put the bobbin in, make sure you pull the thread through the catch (not sure of the correct term) so it "clicks." I was just hurrying when threading it.