Just put a new fuel lift pump & fuel filter on my 200 tdi 110 as it was dropping power down to 10mph then picking up again then slowing right down just gone out in it tonight and it’s still the same managed to get it home never went above 20mph undone the bleed screw on top of filter nothing undone the banjo fitting on side of filter that feeds the filter nothing at all,when I manually pump it there is no resistance does it mean the new lift pump is faulty or some other reason.atb Ed