A few months ago, the two outside wall electrical outlets and an
upstair bathroom outlet went dead, no power. Then all of a sudden, just
let it went out, they all came back. Breakers are showing OK
throughout.

Then a few days ago, I plug in a BBQ charcoal heater into one of the
outside outlet (called #1). At first, it heated up, but later went
cold. I found out later that the same three outlets went dead again.
This morning, I changed the #1 outlet - the wire did not show power.
Nothing, still no power. Can someone give me suggestions on what to
look for and things to do. Thanks.