I recently replace my upper intake on a 96 Bonneville. While I had it off I cleaned everything including the throttle body. Everything is back together and now my car seems to be increasing in “idle”. I shut it off when it got above 2500 and might have gone further. Is there something I need to reset since I unhooked the battery? Vaccum off? Bad upper intake? Leaking through the intake?
But you didn’t replace the lower intake manifold gaskets? You might want to check for an intake leak in that area.