Frankly, if you're going to tear it apart to replace the coils and sleeves you really might as well spend another $18 or so and replace the links & plungers, bushings and coil stops while you've got it apart. There really are no special tools needed outside of a couple wrenches/sockets and possibly an allen/hex.

Take a look at the flipper opto boards in the cabinet on the other side of the flipper buttons, they'll look like this...

http://gallery.myhomegameroom.com/albums/proto_cftbl_progress/DSCN1597.sized.jpg

The metal piece sits down inside the optos (black U shaped things). When you press the flipper button it moves out from in between the optos so they can effectively "see" each other. This completes the circuit causing the flipper to fire. If the optos are dirty or failing, the flippers will not behave well. Try cleaning the lenses with some alcohol on a q-tip. You can also swap them from one side to the other and see if the extra weak upper left flipper becomes an extra weak upper right flipper. That would tell you that you for sure have an opto board problem.