Engine vaccum - 90' Suburban

[SoCalSlaughter]

Thanks for the replies. The timing is set 4 degree's advanced. The vacuum is steady, doesn't pulse or jump around. And the muff is more noticeable at idle. I do think some of the valve steam seals are going, because on cold starts, it has a blue puff of smoke out the tail pipe, but doesnt smoke while driving. or consume oil.