Hissing Intake???

[Ford5.0]

Hey,
A got a 89 townie with the EFI 302. The other day I took apart the intake, from the inlet down the the intake manifold and attempted to clean out the black coating that is gunked all over the insides. Now when my car runs. theres a light hissing coming from the air inlet, and when I turn off the engine theres a quick, loud hiss for 2 seconds that goes up in pitch. It's not the filter, that's new anyways. This ever happen to anybody, did I clog up a hose or something?
Some of my friends believe me for a while when I tell them its a supercharger.....

Thanks

[Towncar]

There's some 5.0 threads running here.

Other than that, I can't be of any further value on the subject.

[ltdltc]

Did you tighten all the bolts to TQ ratings?

[Ford5.0]

Yep, everything is tightened correctly, and I used either gasket maker or a gasket maker/orig. gasket on all the parts. The loud hissing is coming from in the inlet. I don't get it.

[Stoycon]

Originally Posted by Ford5.0

Hey,
A got a 89 townie with the EFI 302. The other day I took apart the intake, from the inlet down the the intake manifold and attempted to clean out the black coating that is gunked all over the insides. Now when my car runs. theres a light hissing coming from the air inlet, and when I turn off the engine theres a quick, loud hiss for 2 seconds that goes up in pitch. It's not the filter, that's new anyways. This ever happen to anybody, did I clog up a hose or something?
Some of my friends believe me for a while when I tell them its a supercharger.....

Thanks

EGR Valve ???????