Or the feed dogs could be crooked too. There's play in where the feed dogs are attached too on some machines, and can affect the path of the fabric.

If your pressure foot wobbles check the screw that holds the pressure foot on and see if the screw is tight. If you don't have the screw tight your foot will wobble.

Is the presser foot wobbly or is the whole needlebar? I had a wobbly needlebar in a PFaff. A straight seam looked like a small zigzag. While my repair man was looking at it, a screw broke. I had him weld it so it now a straight stitch only machine, which is what i wanted in the first place.

Bottom of diagram 3 is where the confusion is now, since the shop lady threaded it differently than we were. I should really take a picture to show you the difference in how my supposedly correctly threaded machine differs from this part of the diagram. I appreciate your time and help. Your recent insructions are a little too technical for me at this time, as I don't even know where the feed dogs are :) But, that is okay because the foot only wobbles if I push it and sewing straight is not a problem. What a learning experience this is! :) Holiday Blessings to all.