Ok so it sounds like I came up with another unicorn idea.
What if I ran the same setup, but killed all the cylinders. The 'key' to reactivate them would either be putting it in 'D' or putting in in 'D' and pressing the accelerator. Then they would all go back on like normal. Or is this no different then a normal kill switch?
Would it need a heavier flywheel if it only ran one cylinder in neutral and all of them in drive?
Going back to wmjinman's point, how do the modern deactivated engines hold the valves open? Computer tells it to stay open, but what actually stops gravity from holding them down? Also do these vehicles have a camshaft? With yhe ability to stop the valve action I would think the nudge (excuse the improper name) on the shaft would need to be out of the way, so it doesn't force the valve down.
Thanks!
Jeff