Same thing happened to me during the 2011 holydays (I also have that special ed).
It had been garaged for a couple of days (3-4) without any activity, in a garage kept at 5 degrees celcius. I had to go to the dealership for something else (they scratched the window on the driver's side while installing the tint) so they checked it out. They came to the following conclusion : BAD GAS. The removed the gas in the tank, and filled it up at shell.
They told me (by email) to stop fueling at PETRO-CANADA, and to stop putting in premium fuel, to go to basic fuel. I did that for a couple of months, and went back to premium fuel, I think I get better mileage from premium. Didn't really notice any change in performance though.
So all that being said, it never happend again, with premium, basic, shell, esso, ultramar or even Petro-Canada (sometimes you don't have the choice).