LOL !
'since new parts were installed' ..it *couldn't be those* ... !

yes, that's an assumption. The exact opposite is true - if it's been
touched or worked on, that is where to look first.
Of course always confirm the success of any new work.
I have said this a million times - it's not in the Parts, it's in the
Workmanship.

in other words, new parts installed with less than total care and
precision are not so good.
You know ..like .really good workmanship with serviceable used parts
will produce a better result than new parts installed not so perfectly.

Sure would be nice if you had another throttle body or two to try.

One of my vans did that whistle thing. It was kinda fun actually.  Lots
of throttle, no whistle.
Let off just right ..distinct whistle, and the engine cover did not have
to be off. I think that was on the intake runners somewhere.

I'm sure you must know about engine torque-induced air leaks..
Say on decel the engine tilt pulls on the Air Intake Boot just right to
create an air leak, and only under those conditions.

Scott
www.turbovans.com

yeah, try not to be a 'parts changer' ..
the ole term  is 'throwing parts at it.' .....not a very smart way to
approach vehicle  repair and tuning.

On 6/26/2012 7:56 PM, neil n wrote:
> At various points had thought to do that but since new parts were
> installed, (runner boots, TB seal etc.) and all *looked* fine, I made an
> assumption. Will check further for any vacuum leaks.
>
> With the engine lid off, and driving, I can hear a brief whistle sound when
> throttle moves through roughly the first 1/3 of travel, under load. Sound
> comes from throttle body area. Will listen with a tube.
>
> @ Alistair: yes yes. I know.     ;)
>
> At this point engine drives ok and I'm being pretty picky. Time to get to
> other issues like the long heater hoses. They look old!
>
>
>