Sport Really slow to pull away

I have a range rover sport l320 2005 drives really well until you stop at a junction or on a hill
Then it is really slow to pull away no power till you build it up
I have deleted the egr new air filter cant see any splits from turbo pipes
Any Ideas what it could be
Would a mag sensor do this

Was the egr valve programmed out? Most ecu's now know when the egr valve is open and the airflow meter can confirm the difference in airflow or it'll fault and give lower power. Any fault codes or engine light?