Drove it to the bank and everything was fine..

Got back in the car and started it up... everything was fine...

Drove out of the parkinglot and went to the stop light and she wanted to idle at 400 RPMs....

WTF

Drove it home and everytime I stoped the R's dropped down to 4-500...

Turned the car off in my Driveway and let her sit for a while...

Came back after an hour and it was like nothing ever happened...? It idled at a normal range..

WTF

 

my guess is you ran over something that got sucked up and clogged your intake somehow, not in the maf or anything but like before the filter....a plastic bag maybe? I dunno...

 

Ive had my idle creep before but the dealership replaced both the fuel sending unit and altenator Don't know if thatll help you just my experience