rangerover cuts out?

rangerover with a 2.5 bmw engine,starts ok when cool,but wont start when hot, unless i bump start it, then it starts great even when hot.when it is running, it will idle perfectly but if you if you just take your foot off the throttle from a high rev it cuts out.i have had the fuel pipe off going to the filter and when the ignition is on nothing happens until you put it into the cranking position,then fuel is emitted.performanc is still unaffected.no faults on computer