Pressor foot will not move down. How do I fix that?

How long since it has been serviced? Sounds to me like it may need some cleaning and oiling.

You need an embroidery foot, that doesn't lay on the fabric like a normal foot and allows free motion of the fabric. If you are using one, be sure it is the appropriate foot for your machine and that you have pushed the appropriate button or place on your machine so that the machine will place the foot in the correct position.

Oil is placed where there are two pieces of metal rubbing together.
1. You must look for moving parts while moving the hand wheel. 2. There are some holes on the frame to give you access areas that need to be oiled..
3. The bobbin rides on an indented area called the race. Place one drop at this location frequently.
4. The motion of the needle arm going up and down between two holes needs to be oiled.
5. The pressure foot has a movement of a steel tube (arm) that needs oiled every now and then. The up and down motion of the pressure foot switch has two pieces of steel rubbing together in order to raise and lower the foot. It is important to oil here and on the spring that is inside the tube.
Anyway; make sure you look for steel against steel and oil it.

You need a special foot for free motion quilting--it is slightly shorter in height than a regular presser foot, which essentially provides space between the presser foot and the needle plate to manually move the fabric. Sometimes machines came with a standard darning foot accessory. Your Pfaff dealer probably has at least one style in stock. But there are other specialty feet you can probably use, ie Big Foot, clear free motion foot, C-shaped, oval, etc. You can also purchase a shank adapter (verify it is the correct shank for your machine) and use it with a kit of snap-on presser feet so you can have a variety of presser feet for different functions.

Pfaff Presser Feet

Pfaff Big Foot Free Motion Quilting Foot

Pfaff Free Motion Guide Presser Foot

Pfaff Free Motion Open Toe Quilting Foot

http://www.sewingpartsonline.com/snap-on-sewing-machine-presser-feet.aspx

http://www.sewingpartsonline.com/snap-on-sewing-machine-presser-feet.aspx

Free Motion Quilting

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Depends on your machine brand and model. Some machines have that capability, others do not. Consult your owner's manual.

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You really do need a foot (just a smidgen shorter than a regular presser foot) that does not contact the feed dogs in order to darn, couch, or free motion stitch. The whole idea is that with this method the feed dogs will not move the fabric, but you also need the foot that allows extra space for you to freely move the fabric manually.

unless it has been progressively getting slower, I did have a simular issue. My pedal was getting "stuck" at the 1/2 mark. (wasn't pressing all the way down). Drove me nuts. Took the machine apart, cleaned oiled, cleaned again blah blah blah...when the pedal was the last option took it apart and found a nut from a screw had gotten inside the pedal and stopping it from pressed down. There could be a burr, a nick or something it is catching on.

Perhaps you accidently moved the switch that enables free hand embroidery? It's up and under next to the pressor foot lever. Slides forward and backward. Forward the pressor foot will go all the way down to the feed dogs. Slid back and it keeps the foot up off the feed dogs but allows the thread tension to work properly. It would be easy to accidently move it when operating the pressor foot raise/lower lever.

open it up and lubricate that shaft with vaseline..or vegetable oil..work it up and down.. may be just stiff..

There is an in- between setting. It's not up, but not down either. Does that make sense? If you put the lever up, then bring it down slowly and kind of push it to the back. Hope this helps!