Now, i don't really know all THAT much about vacuum pressures and whatnot, except that larger cams cause lower vacuum pressures, and that when you are opening the throttle more at lower rpms the vacuum drops significantly fast. Also that when you are decelerating at a high rpm with the throttle closed, the manifold pressure is extremely HIGH, like more than -650mm/Hg sometimes. But, this is something i've NEVER seen before, an NA car that made a 0.00mm/Hg vacuum reading; lol if it had gone any further positive, my map sensor would've lost its mind, i know that much.