Strange Noise

[Gman]

Me again, another noise i have not heard before wonder if anyone knows what it could be.

After acceleration and about 0.5 reading on the boost gauge when deacceleration is when it happens and i can only describe it as a kind of low pich noise that seems to travel from one side of the car to another.

This makes me sound a bit nutty but its happened 3 or 4 times - not everytime i drive it though.

[Glenn Butcher]

Hmmm Graham - more info.

Which side to which side?  from the engine bay you think?  or could it be suspension?  any particular revs?  brakes? etc.