HELP ITS DRIVING ME MENTAL NOW!!

[Supermarine Blues]

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,

Nah, do it again!

If you can play 'Stairway to Heaven' on the IACV ports, that's it.

Otherwise, crush/pinch every bloody pipe on the thing until the pitch changes.

80% it's the IACV or tensioners.