replaced the metering unit and all is well, MY MISTAKE WAS TAKING APART THE HEAD OF THE UNIT, the petrol gauge is getting a little lazy and although there was fuel to the filter it was dregs. fuel pressure gauge would of told me this in the first stage and saved me money and time.
i took the metering unit apart previous and replaced the o rings, it would
appear the o rings i put in were the wrong size, i would recommend going to ford
for the correct ones as mine were out of a multi pack with every size, ther is a lot of pressure in these units and altough the rings i replaced looked the same they oviously are not. could of possibley of been a worn shaft in the centre of unit.
DONT TAKE THIS UNIT APART CHEAK FUEL PRESSURE FIRST.