renault master 140hp?

no-one (inc main dealers) can get this van to run for more than 1 day
it has done 70,000 miles (prob started at 59,000 miles)
it has had new pumps, new ecg, new injectors 4 twice new crancase sensor 3 times. new starter motor, new battery.....the engine is a demik. renault said it is my fault i should have bought the 120hp
every time something is changed the van starts 1st time but will not start without a tow or easystart
any body got same prob?????