Please can anyone help

Sorry I could not find anywhere else I could post this for help

I have had my Maverick 2.7 1994 for four years now and it has never let me down once until now. It packed up about two weeks ago and would not start. I changed the glow plugs last night and charged the battery and now it starts. The problem is it runs fine on idle but as soon as you rev it it coughs and splutters and wont rev up. If however you hold down the hand primer it revs up. also I changed the fuel filter but it made it worse and had loads of smoke from the exhaust. Can anyone help please ?
Thanks
Marc