What Janome machine do you have? All my Janome machines have foot pressure tension adjustment. How many years of use? And is the use heavy or moderate? If lots of use, you can wear out feed dogs. BTW, most techs do not use a quilt sandwich or pieces with seams to test machines during cleaning or check up. If you are having the problem without the walking foot, then it is not the walking foot. Check your foot pressure knob and increase your pressure. Hope there is an easy fix.