Electrical Outlet Replacement

[Cm1384]

Replacing several receptacles in my new used home. Some difficulties however....

The priors decided to spray the expanding foam insulation directly into the outlet, where the wiring is housed. This 'glued' everything together in place and has made it quite difficult to remove the old outlets.

However it is doable, just a pain. My question is this...
Several of te outlet boxed seem "loose" behind the drywall. One is especially and it seems impossible to plug anything in because when I push, the outlet just sinks into the wall. I cant even attach a cover plate, as the outlet is so recessed. What do?

[thedcdude]

I assume the boxes are attached to studs. Some times you can pull the box into position and then drive a screw from the inside of the box into the stud to tighten it up. If the box is metal you will have to drill a hole first.

[pushkins]

Or carefully pry the loose box free of the stud, remove the wires and reinstall an "old work" box.