I know there are a couple of these faults in the archives but there seems to be no fixes even though there may be a variety of fixes for these codes

So heres my symtoms and maybe some one can help me narrow down the fault.When driving the van, it drives perfectly untill you get to 3000rpm and under load then the van just dies, but it starts up straight away.
When it starts it has 280 bar rail pressure ,stationary position and max rev it has 1070 bar with no problem .But when driving under pressure and it hits 1570 bar the pressure just falls away and the van cuts out.It starts perfectly and drives untill its put under pressure again
On doing a leak-off test for 5min the fuel amounts are the same at 40ml, so I think I can eliminate the injectors.I bypassed the fuel filter but the symtoms are the same. I was told by Ford tecs that its may be a imv but just looking for some input as they are not 100% sure.