Hissing and Vac/Fuel Testing

I have this weird hiss/whistle that is coming from the front of the engine manifold area. Its relly hard to tell over the exhaust / engine sound but everytime i look at it i get the feeling the hiss is coming from the fuel rail area.

I have purchased a vac gauge and connected it to my manifold (in place of char canister) and it swings from 16-17 Hg @ warm idle. I am not sure what its supposed to be but that seems a bit low to me. The manifold bolts are tight (just installed new apn exh header) and the vac hoses seem to have no effect when i disconnect them and block their inputs.

For the most part the idle is ok, hick up here and there but i guess acceptable. Should i test the fuel pressure next ?

pete

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Buy a can or 2 of carb cleaner. With the engine running, spray it around any place that draws vacuum. If the engine stumbles where you sprayed it, that is more and likley the source of your leak. HTH.

what year? My renix had this, line was in wrong spot and a tube was sucking. easy fix for me.

94 XJ 4.0

pete