Fine point/technical question.
Your driving your Westy on a noticeable upgrade.  You notice that you
have your foot to the floor but are not gaining speed or revs on the
engine.  You back off a little on the foot feed and nothing changes!
You keep backing off until the engine/van starts to slow, keep your foot
there and continue to cruise at whatever speed is the max for the slope
you are pulling.

Now the question is this.  When the pedal was all the way to the floor
but you were not accelerating, were you pumping a whole lot of extra gas
into the engine that was being wasted?  Or does the ECU keep the fuel
flow to the most efficient amount even if you were asking for more fuel?

Inquiring minds want to know....