I also have a Janome and have had problems FMQ when I first got it about 6 years ago. As suggested, I also use the same color thread in the bobbin as in the top. While struggling to get the tension problem solved, I found that my thread was snapping frequently. What I did, and it seemed to solve both my tension and thread snapping problems is that I don't put my thread through the last threading station. You know that tight hook just before you put the thread through the eye of the needle. It really helped me.