hi, after taking your advice about the lack of power in my 1.8D 55 non turbo van im still in the same situation. its still has no power it doesnt smoke. it revs up fine when idling but theres just no poke when driving (struggling to get over 50 mph) ive changed oil/filter, fuel filter, air filter....whats the next step would you check the injectors or is it more likely to be a fault with the fuel pump?

advice is appreciated.