Is it possible to have a vacuum leak around the Throttle body.

[LeeS97Z28]

Hi Guys!

It is possible to have a vacuum leak around the throttle body where the butterfly is on the throttle body. The stem that opens and shuts the throttle plates or butterflys.

I can hear a hissing sound but i don't know if it is coming from inside of the throttle body.

How many of you have experienced this? My throttle sticks sometimes because of the throttle body.

Thanks Lee!

[Injuneer]

There is actually a "seal" on the shaft where the TPS sensor mounts. Its a little circle of foam... maybe red. If that's missing you might have a very small vacuum leak.

There are also three gaskets involved.... top plate (not under vacuum), bottom plate and TB to intake manifold (both under vacuum). And there is an o-ring on the IAC motor. and a vacuum port on the passenger side of the TB for the EEC purge solenoid, which can leak.

And the little hole at the bottom, between the bores, for the IAC air inlet will sometimes "whistle" a little.

And directly under the TB, on the front of the intake manifold is a vacuum port for the line to the PCV valve.