is it smoke or steam? if it's smoke, it will linger for a long time. if it's steam, it puffs, but doesnt linger for much more than seconds when you're moving.

easiest way to tell is to simply wave your hand thru it and feel if it's wet.

if it's not wet, it's oil burning. rich fuel settings will result in black smoke.

excessive steam and the odor of coolant is the result of a blown headgasket.