[mwebb]

if the engine is not running because the
injector supply has been opened
then
the car should be rolling in neutral and the engine should not be turning

so
while interesting to ponder , there is no reason to use engine braking for this condition
============================
EGR does improve FE ...
where are you going with your comments on EGR ?

Originally Posted by drbobwoolery

Opening the injector line allows WOT with no fuel. If the "pumping losses" are as significant as some on the EGR for MPG thread suggest,

engine braking should be reduced by opening the throttle while coasting downhill in gear.

So if my 91 calif. Metro goes noticibly faster down my test hill with the throttle open than shut, then reducing output by adding EGR up to the misfire limit and keeping the throttle open will pay MPG dividends. If coasting down the hill in gear, inj. off, throttle open does not go faster than throttle closed, then the increased EGR is a dead end.