Chances are egr hose. under the thottlebody there is a hose that runs off the intake to the egr, then another hose running from the egr to the exhaust manifold and it recirculates exhaust to be reused( dumbest idea ever). Well anyway the tubes tend to crack on the edges undernieth the piece that holds them to the intake or egr so you cant really see it without taking the hose out. These hoses for for like 40-60 each at dealer so alot of us say screw it and remove it completely, cap off the holes, and tune the code that will appear from the pcm. Try taking some carb cleaner while the car is running and spray it on the vacuume lines and those egr hoses, if you hear increase in idle then you found your leak.
