finally got to the bottom of this and found out the problem exhaust manifold leaking ,took it in to my local indi and they have stripped it and sent the manifold of to be machined ,hope it solves the problem.

Just as an outside thought, the crankcase breather. Have you fitted the newer version at all?

Are you getting a good boost reading when it's picking up? If you have diags your welcome to pop by and we can compare apples with apples? FFRR MY06 facelift With TDV8 Alloys Zeros/ATR's
Mantec Sump Guard, Rigid Load liner, MY10 BT upgrade.

yes i have fitted the later crancase filter ,havent got it back yet from indie

That's good as that's been known to cause turbo failure. FFRR MY06 facelift With TDV8 Alloys Zeros/ATR's
Mantec Sump Guard, Rigid Load liner, MY10 BT upgrade.

I think mine has this same issue. has had for quite a while now. just out of curiosity, how would I diagnose this and how much to remedy?

Rory.

got mine back from garage all fixed did the manifold changed both belts ,400 pounds,bargain i thought it takes 6.9 hrs to change exhaust manifold gaskets,also changed the down pipe if yours has got a aftermarket one one ,it makes a zinging noise up the rev range as though you have got a leak .

That's exellent news. You won't have to worry about that issue again.....

 2011 Range Rover Vogue SE 4.4 TDV8

Previous cars :
2003 Range Rover Vogue TD6
1999 Discovery Td5 ES
1995 BMW M5 3.8 6 speed
1992 Range Rover 3.9 Efi Vogue
1992 BMW M5 3.8
1988 BMW 735i SE
1989 Ford Sierra XR4x4 2.9i
1981 Ford Fiesta Supersport