Daewoo Nubria Drama Low Idle/Cuts Out Easy

[DaewooDrama]

Soo I have a Daewoo Nubria 1997 1.6l. I have had all the heads reconditioned about 2 months ago plus a new radiator.. Now 2 months on it seems to be running rough when just on idle and when driving it seems like its only running on 3 instead of 4 cylinders. I changed the spark plug yesterday (the one which burns out quick unsure why??) and its still doing it.. I have noticed since i got it back from the mechanic it is sometimes cutting oout when on low revs when nearly stopped or semi rolling it just stops.. Any help on the issuses would be great? Ive only had it 2 years and it would be one of the worst i have owned

[woo99SE]

did you checked the idle speed control?
any cel codes?