Electrical Outlets Seem to be Blown but not the Fuse
Hey Bub is right on the money.
Stab in connectors usually fail when there's a high electical
load--like a shop vac. They heat up and lose their spring tension.
After a few rounds of heating up, they're worthless. Every time I've
seen this problem, it's always solved by replacing the receptacle and
using the screw terminals rather than the stab in connectors.