Managing EGR for MPG

[JanGeo]

you are forgetting a couple of things - first the gasses will have cooled at the tail pipe and on the way back in the hose to the intake, second is the load is light when vacuum is high and that's when you need more exhost recirculated and that means low exhost temps anyway because you are not burning a lot of fuel - plus less O2 would inject less fuel and you will loose power that will require more throttle and more air and lower pumping losses . . . exactly what you want.