@parados,
Mice can chew through electrical wires. This could be causing an intermittent short. An electrician is probably in order
If I was trouble shooting, I would disconnect the electric for those outlets and check continuity and resistance.
Is wire size in the wall correct? Too small a wire can cause loss of power but also causes wires to heat up. I guess it probably isn't a good idea to assume the person that originally installed those outlets did it correctly and to proper code.