Rough idle and hissing sound.....

[FordExplorer18]

I found the hose that is hissing it comes from a black canister on the drivers side firewall. Then goes up to the "vacuum tree" on the intake. The side closest of the little quarter sized one way valve is hissing really bad....can that little one way valve go bad and need to be replaced or what? Thanks guys.

 

[Commtech]

I had a vacume leak once. Had a backfire that popped a hose off... When I started it again the engine ran terrible. I was wondering if I could make it to the shop. I couldn't find the leak as it was under the intake riser and I couldn't see what had popped off. I thought I had done some real damage with the backfire

 

[mrboyle]

From your description it sounds like the leak is the grommet for the check valve on the power booster. You should be able to find a replacemet at any part store.

 

[FordExplorer18]

You are talking about the little one way valve in the middle of the hose right??? Thanks