Hmmm. Thatks tinker, perhaps that might be the issue. It was really quite cold the day it was installed, and maybe the gasket wasn't quite seated. I'll look at that when it warms up. I know that my mpg's really decreased this year, more than normal, but I was attributing that to the run rich and lagging issue. The mpg's seem to have gone up a bit, not as much as they are in the summer, but I've found that to be the case with the cold temps and slippery roadways anyway. But given the lack of snowfall then the MPG should have been closer to the normals that I get in the summer. So maybe we do have a gasket issue.