We live in a mobile home and one of the lines has gone dead, I have replaced the breaker, and all of the outlets and switches on that breaker, and still cannot find where the bad spot is. it has mysteriously come on, but eventually goes back out, and hasn't came back on in some time. Is there some way to trace where the problem is?

 

It sounds like a bad connection at the first junction in the line.. When you say youve replaced all the devices, did you happen to check any wirenuts in the boxes for looseness? The offending nut may show signs of scorching/melting.

Also, if this is an older trailer, did you happen to notice whether the wires are copper or silver colored?