i think i`d test each one of the outlets for a bad connection. you might check you`re connections at te breaker box. even a loss lug or maybe a bad breaker might do it. while i`ve chased down alot of electrical grimlins, i am not a licensed electrican. be safe and only turn the power on when testing. remember too that a bad connection can heat up, arc, ect..., possibly causing a fire. i wouldn`t put any load on that circuit until i figured it out. good luck.