The other thing my mate tells me, is that the engine keeps going into what he calls Limp mode.

Where he can hear hissing when the turbo is on boost and then 10secs later it goes into Limp mode where the engine will not rev anymore than 2500rpm and the engine mangement light is on, also its drinking fuel.
He has checked the hoses etc to his best, finding everything ok.

Any Ideas what could be causing this problem.

thanks

Ok I've found the fault.

Its the rubber hose joint from the turbo to the plastic pipe going under the engine to the intercooler, it was split.

New hose fitted and its flying again.