I too would question if the outlet doesn't have an issue. A loose wire or the outlet itself going bad. I have found that transient issues with outlets can be very tough to diagnose. I hope you don't need an electrician for this, but if you don't know how to troubleshoot household ac, I would be cautious.
Home Theater Man Cave: Onkyo 7.1 Klipsch LaScala Mains, Shortened LaScala Klone Center, Klipsch Academy Surrounds and Rears; Panasonic AE8000, Panasonic BDP 460, 117" DIY Screen.
Garage Man Cave: LaScala Industrial Splits; Second hand Denon Amp