89 YJ has rough idle, but runs smooth in the higher RPM ranges. Pic attached of a Manifold and TBI (not mine but similar). When I spray Brake/Carb Cleaner at or near the Vacuum Tubes (arrow) the idle smooths out for a few seconds. Pretty sure this indicates a hairline crack in one of the tubes. I am thinking of a wire wheel cleanup, then paste some JB Weld over the suspect areas. This because I want to avoid re-doing all the tubing, or spending the weekends in wrecking yards looking for replacements. Also wondering if 2 of those Vac Tubes go to the Front Axle CAD Disconnect, which I am thinking of replacing with a Posi-Lok.