Engine smoking

Light colored smoke out the exhaust is normal until the engine warms up, especially noticeable on cold mornings dense air. Blueish/gray smoke is a sign an engine is "burning oil", excessive black smoke would be a sign an engine is running to rich/too much fuel is entering the engine. White steam perhaps noticed with a slightly sweet odor from the exhaust, rough engine running, over heating and or coolant loss would be a sign of a blown or mildly blown head gasket.

I suggest checking your a sticky PCV valve or restricted PCV system. Also it's also possible for the oil to leak through the valve stem seals and collect in the cylinder before you start the Highlander. Make sure you change your oil at regular intervals to ensure preventive problems like this. Thank you, Sam