hey guys im trying to track down the cause for my low vacuum..
15 at idle
12 in drive


im getting a whistling noise from my throttle body and i cant figure out where its coming from... i replaced the throttle body with a junkyard unit and it still had the same whistle noise and low vacuum.

i reused my IAC and gasket on the new TB and when i was listening to my TB with no intake ducting on today i noticed the high pitched whistle was coming from the IAC area but from inside the TB..

is this normal for the iac hole in the TB to have a loud whistle like that?


every possible vacuum line has been replaced and all gaskets except for the IAC gasket.

 

I think that it is just the air whistling that is comming into your TB. Mine does the same thing at partial throttle. You shouldn't have anything to worry about. Your TB is open just enough to get the air to whistle.

 

Vacuum is good. Don't worry about it. When i had my 2.8, the vacuum was always around 15, and will drop to 12 when the car is in Drive due to increased load and lower engine speed.
My 3.1 only gets up to around 16-17" Hg vacuum, so there isn't much difference for the 2.8. Either way, some service manuals say that 15" is extremely good for our cars. If it drops below that, however, then I would look for a leak.