Almost under the cam stack - below the rectangle thingy is a plunger or piston type part - moves horizontal - it has it's other end on the needle bar. If you push on the needle bar you can see it go in and out there - follow the part to just before it goes under the camstack - see it go in and out? That needs to be cleaned with solvent, too - drape off the painted areas of the machine and use caution.