Rough Idle on 89 YJ 2.5L

Smiling_JIm

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Joined
Jul 9, 2022
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Menifee, CA
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.

89 YJ Intake and Throttle Body pic - 7-09-22.JPG
 
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.

View attachment 120119
What may be easier is to find the bad spot in the line, cut it out and put back together with a brass compression coupler.
 
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