do no harm to check the glow plugs if it is bad to start first thing in the morning,you could also check the fuel piping for drawing air,check for chaffed pipes,rubbing through especially in engine compartment,dont know on this model if it has a hand primer at the filter but these are usually a source of air in the system,it is very difficult to say if it is the pump but would leave that as a last resort because of cost/time, the most trivial fault on modern motors now can cost a small fortune to repair so next time dont get landed with a lemon,good luck
wickham
August 2010