Lude Generation

I have this high pitched whistle that has appeared again, it did go away but could be heard when switching engine off for a split second as the revs dies,, now its back, a very loud high pitch whistle at idle,

So far I have replaced the whole inlet manifold, bypassed the black box under the manifold
changed the gasket on the throttle body
changed the valve on fuel rail
checked vac pipes
sprayed WD40 everywhere to isolate it
made sure vac pipes are in the right places

I cant pinpoint this drokking whistle, its definitely round inlet manifold somewhere, brand new gasket nuts are tight, exactly the same as before manifold swap.

Other things I should add is the flat spot seems worse when the whistle happens
I can hear like a groaning sound somewhere in the bay like turbulence

its pissing me right off

Its not often I am beat but this is getting the better of me this time, please help!

Are you sure it's not the alternator/belt tensioners/water pump and the intake isn't a red herring?

The idler on my S2000 used to screech in VTEC because the bearing was dry.

I am 100% its inlet manifold area, its only at idle too, rev to about 2k and its gone, drop back towards 1k and it comes back, affects throttle response too. no codes, vtecs perfic not lumpy in that rev area.

Just guessing, but could it be something like an iffy gasket on the inlet mani?

Or a hairline crack (no, not a Brazilian!) in either the manifold or one of the myriad of rubber pipes.

I wonder if you could use WD40 or water or somesuch on each bit separately until it STFU.

what intake do you have on it?

One from a previous breaker which I know was good, it has a fresh gasket and its the second manifold on the car, I replaced the original for this reason.

SB did wd40 test, no joy, googled it and others have had it

http://honda-tech.com/showthread.php?t=2064942

nothing conclusive though,

no not the manifold the intake piping?

mine was from the throttle body i think it was from the IACV port, try taking the intake pipe off an cover the hole for it and see if it sorts it, it would explain why it doesn't do it when not idling.

Mine was air con tensioner