EGR, Idle Air, and downhill pumping losses

[Daox]

Yep.

[ConnClark]

One thing that needs to be considered if your going to tamper with EGR and Idle Air is you may end up fouling up your catalytic converter. Cars now days tend to run a tad rich to control Nox. They are intentional given short burst of lean conditions to help burn the cats clean. messing with EGR and Idle Air may upset the balance.