vauxhall zafira 1.6 51 cuts out and wont start again 4 a few minutes!!?

my vauxhall zafira club 1.6 51 plate will start and run normally then as im driving along i sometimes feel it start to shudder and as soon as i slow down it cuts out completley and wont restart for about 5 mins..the crank sensor has been changed but it is still doing it! also nothing shown up when plugged into a computer..any ideas?