a few months ago symptoms started out as surging idle, cleaned the FITV and IACV and surging seem to be gone but now idles at 1500-2000, replaced the FITV and problem seem to be cured but not entirely and now this happens...

black smoke coming out of exhaust, running very rich, idle very crappy and have to stay on gas to keep engine from dying. checked engine oil and was shocked to see it was black as mud after only less than 3k since last oil change.
when i pulled out the spark plugs, they were fouled-up, and there was smoke coming out of cylinder number 2??? replaced plugs with new ones just so i could drive to work. CEL would come on sometimes but haven't checked what code yet.

help?

 

any advice what i should do?

 

Get the code checked too see what the problem is.