unstable engine

[daddybird]

I have a commodore vl 2.0 with Nissan Engine which was recently just doing fine. After last week the idle was not stable and if it it is on the lowest idle the engine runs so rough having black smoke seems like choked from the inside. when i check out the spark plugs it has black carbon on it.. i decided to change to new spark plugs then it runs smoothly again on it normal idle after a week later again the problem starts again. i tried changing the ignition coil it helped a bit but still there is the rough engine running then after a while the engine would stop.

Do anyone of you guys have the same experience maybe u have some ideas on how to solve this problem.

Thanks
Kim

[nasty1]

Have you messed with the timing? Sounds very rich to me

[daddybird]

im not quite sure if i've messed with the timing.. but if in that case how would i fix this thing

[nasty1]

have you moved or adjusted the dizzy?

[daddybird]

the screw type to adjust the air flow? ya i have adjusted that one

[nasty1]

The dizzy has all the leads plugged into it

[87RB30VL]

How're your leads?