I've noticed if I switch from "ECO" mode, or back into "ECO" mode with the heat on, I can get the ICE to shut down when stopped. I don't know how/why this happens. Also, the ICE seems to come on with the heater on even if the engine has warmed up to the normal operating temperature.

I knew the air conditioner would affect my FE, but I never thought the same would be true of the heater.