Right here goes.A few months ago my hdi 110 started to hesitate under accerlation.Maybe once a week it would feel flat for a second,then would take off.Anyway,after being parked up for a week & a half while we were on holiday,the problem was worse.About 50% of the time the car would feel & accerlate fine,the other 50% it felt as if someone had put the brakes on,or pulled the intercooler pipe off.I changed the fuel filter last sat,& had metal bits in the housing.Over the years I have had bit in the filter housing but not this bad.Took the car out & the problem was still there.Then I cleaned my k&n air filter which was quite dirty.Problem gone,car feels quick & responsive.Lovely I thought.Untill today.Coming home from work tonight it was terrible at times.Put my foot down to overtake etc,hardly any extra oomph,then bang,it would take off.Even when its misbehaving,it still revs past 3K,so its not as if limp home mode is activated.There is no eml light on,no excessive smoke,mpg according to the display is spot on,it starts perfect,& runs smooth.I`m thinking maybe the lift pump is getting lazy.Going to try the egr blanking trick tomorrow.
Anyone any other thoughts.

182k miles now,all original pumps,injectors etc