A new sound to worry about

[Andyjdmteg]

So,
Driving back home last night I decided to give the old girl a boot down the dual carriageway. And a new noise has presented itself in the form of a chattering sound coming from the near side front at the last 1000 revs. It's not doing it constantly I.e every time you floor it.
It almost sounds like the low chatter from a dump valve on something like a scooby at low rev changes. I've had a look to see if there's any loose trim underneath and can't see anything. Has anyone else experienced this? The car seems to be in good health otherwise it's not long had a full service with valve adjust, two front arms and a wheel bearing. Oh and new discs and pads. understandably I hope this sound isn't expensive.

Also if anyone's read my supercharger post I still haven't bought anything to play with. works been crazy.

 

[johnny 5]

does it make the same sound when under strain (such as pulling away from a speedhump in 2nd gear)? If so, might be the cat heatshield.

 

[Andyjdmteg]

No it only happens on hard acceleration near the top of the Rev range. It's intermittent.
I'm now getting a loud groan/screech when pulling away in first sometimes. I checked under the bonnet and my p/s resovoir has come loose from the car? Almost as if it's jumped off the bracket. I've replaced it and it hasn't done it since.