Strange issue with my 3.0d S (X250), started with a flat spot between 2800 and 3000 rpm, which then developed into no power/boost after 2800rpm, and has now gone to no power/boost at all. Car has been plugged in at local garage and is showing no fault codes, there is no smoke from the exhaust, car also starts fine. Boost hoses have been checked for leaks and none have been found. Intake doesn't seem to be sucking any air in at all really, undertray was removed and can see the actuator on the n/s turbo working, there is a small leak of exhaust gasses around one of the upper sensors on the dpf, other than that they can't find what's wrong with it. Anyone have any suggestions on things to check before I have to get it trailered to a jag indy?