However, I've now noticed (without the noise of the radio!) that if the throttle is blipped or "stabbed" from idle, there's a momentary burst of a hissing sound coming from the top / rear vicinity of the engine (throttle body/manifold area) just before the engine revs pick up. I wondered if perhaps an air leak had developed, but the car seems to drive ok (no warning lights etc).
It's a strange sound I've never heard before coming from any car!
Has anyone any idea if this is normal on this engine
