So it runs uneven when you're cruising at a steady 30?
And not when you boot it when you're doing 30!
Dunno much meself but trying to pin down problem
I've followed this guide and sat and watched the subtleties of how the gauge needle moves and what it's telling you.
Vacuum gauge, the wonder tool
Or, if it's been dyno'd and was fine mebbes the dizzy's loose/moved.