Citroen picasso diesol 2003 model

[alotmentman]

hi all hope you are all well ..i have a problem with my Citroen picasso diesol car ..the fault i have is that the car is losing power ie accelaration ,,,after i have driven it for a five mins ie when i start it up there sometimes full power on the accelerator yet when i drive it say a mile theres loss off power i can put the accelaretor to the floor and theres only slight power ...the fuel tank as been taken off and clean also the fuel pump in the tank as been replaced by a universal inline fuel pump ...but i have still got the problem of loss of power please help all fuel filters been changed is there any fuel regulator switches etc that might be at fault ...when the car does have full accelaration it runs fine then fault comes back fuel been replaced several times even used injector cleaner thanks