I checked on the technical bulletins on that vehicle and there is no common problem with this. What comes to mind is this. Cold contracts objects and heat expands them. So using that logic (or nonsense) Could you consider looking around under the hood the next cold spell you have or when you note the smell most. Don't start the car but activate the key to "on" and check around the fuel filter, the injector rail connections, vac lines off rail, injectors themselves and their seating, and finally around the throttle body to see if you can narrow the problem down with sight for leaks and nose for smell origination.
I am thinking that an o'ring, or connection is contracting when cold and allowing a small leak but seals right away with any temp change.
Please consider a to help us answer more questions.
Wednesday, January 31st, 2007 AT 2:24 PM