Sucking noise from my DB9?

[NTEL]

If the throttle pedal is slightly depressed at idle, just enough to raise the engine speed by just 100 rpm or so, I can hear a loud "sucking noise" / "release of vacuum" from the area under the black centre cover / off side inlet manifold. Is this where the crank case ventilation valves etc are located and is this normal? I'm sure I can hear this noise when driving too.

Also I think the engine may be over fuelling. I am driving it really carefully at the moment and it is still only returning an average of 16 mpg. (Only had the car since Easter and not done many miles so not got to grips with what normal fuel consumption is)

Checked for any fault codes and nothing is showing on the OBD2 reader.

Any info would be appreciated

TIA

Dave

[V8 Animal]

Don't know what the sucking noise is,
As for MPG I can't get above 20 with mixed driving in my V12

[AMDBSNick]

V8 Animal said:

Don't know what the sucking noise is,
As for MPG I can't get above 20 with mixed driving in my V12

You need to grow a pair Paul

[V8 Animal]

AMDBSNick said:

You need to grow a pair Paul

Don't tell me nick you get -20

[NTEL]

Ah bóllocks! Somethings not right. MPG down to 15mpg driving like a pussy. Sucking noise is always there. Can't wait or be arsed with the dealer so the manifolds are coming off. There is definitely a vacuum leak causing over fueling. I reckon its on the engine side of a PCV valve.

[V8 Animal]

Gone back into TVR mode Dave

[NTEL]

V8 Animal said:

Gone back into TVR mode Dave

[8Tech]

NTEL said:

Ah bóllocks! Somethings not right. MPG down to 15mpg driving like a pussy. Sucking noise is always there. Can't wait or be arsed with the dealer so the manifolds are coming off. There is definitely a vacuum leak causing over fueling. I reckon its on the engine side of a PCV valve.

Whilst you are pulling them off and spending on the gaskets, you may as well do the plugs whilst you are in there.

Would like to see pics of the job too and what you find lurking in there.

[simonpa]

Get a bit of hose - stick one end against your ear and push the other end around the engine and see if you can locate the leak.
Old-school tech..

[V12Vanquish]

Have you checked for any stored OBD codes. If these is a vacuum leak, I would be surprised if there are no error codes present.