I have a st200 and have started to get a strange noise when my engine is cold. it sounds like ccross between a fog horn and someone blowing across a milk bottle. it stops when the engine warms up or you pick the revs up.

any help will be greatly appreciated.

Its called "moosing" mate. Basically cos it sounds like a moose call. Typical of the V6 I'm afraid. There are aftermarket bits you can change about to minimise it but it is a common complaint. In solving moosing, you may well replace it with a whining noise when the weathers hot.

Have a read of this

it usually happens on pre 2000 reg cars as a modified pipe was fitted after that date,

It is caused by a resonance in the air intake system which causes the idle control valve to resonate. It is this resonance you are stopping when you squeeze the pipe as it is the intake to the idle air control valve. It can also cause the idle speed to be unstable as the valve opens and closes erratically.

Its called "moosing" mate. Basically cos it sounds like a moose call. Typical of the V6 I'm afraid. There are aftermarket bits you can change about to minimise it but it is a common complaint. In solving moosing, you may well replace it with a whining noise when the weathers hot.

Have a read of this

cheers mate youve releived a headache,

You're welcome matey.