rednault scenic?

when cold it starts like a tractor for about a minute then runs ok. grey smoke and fuel smell from rear of car.check ignition was on display once.have applied voltage to each glowplug and each show a load.have yet to apply multimeter to glowplugs to check resistance.garage up the road says injector no 2 needs replacing. surely it would say on comp in workshop?dont see how if it runs ok when warmer???

any ideas fellas????