Does the thread only bunch up when you are doing FMQ? I think I have the same (or similar) machine. Mine is the Brother Disney that also has the Embroidery unit. I bought mine back in 2001. If yours is about the same age as mine, have you had it cleaned at all to clear out all of the fuzz that builds up inside? When my stitching starts to get wonky I know that my machine is way over due for a cleaning.