My transit van 2.5 diesel runs rough at 65?

make sure its getting full throttle ,sounds like fuel/air starvation? check fuel tank for foreign matter which will be sucked to outlet pipe when engine at full demand,check tank unit filter [if fitted] for blockage,and metal pipes on same for corrosion. check banjo bolts and unions on filter and pumps to make sure they are not blocked internally,also make sure lift pump is ok [think this engine has one].also make sure there is no obstructions in air intake system pipe work/hoses/butterfly flaps etc when on full throttle, hope this helps

k
December 2012