Ghost engine idles

my 98 honda accord still runs after i shut it off.i think it is the fan belt.the car smokes and idles up and down when i drive more than 10 minutes. I need a mechanic thats reasonable i live in chicago kenwood area help.

Could be the timing is set wrong. Could be there’s a buildup of carbon on the piston or combustion chamber. Can’t be fan belt because both fans are electric on that car.