Open the TB and try to see how nasty it is in there. I find it easy to remove to clean it and this allows you to look around a little closer. Use caution spraying in the area where the rod goes through the housing.

Have you sprayed carb cleaner or something like that all around the intake area while the car is sitting there at idle? When you hit the area where it is leaking it will increase idle slightly.

Do adaptation after cleaning.

__________________
Jim