Very Low Gas Milage In Cold Weather. Why??

[Hirudin]

I had a come-and-go CEL, finally took my MS3 ('07) to the dealer today. Here's what they did...

Customer states check engine light is coming on. Performed the diagnoses- Found IMRC bank 1 stuck closed. Inspected and tested the valve- sticking=needs valve
Noticed bottom mounting bolt for the valve is broken inside mounting hole
Installed the valve and repaired its mounting holes

They also did the "OBD-II Compliance" recall thing during the same visit so I wont be able to tell if I'm getting better mileage because of the IMRC being fixed or the recall... (I hope I get better mileage from one of these repairs...)