There is white smoke coming out of the tailpipe, and the car is sluggish when switching gears.
The combustion process gives off a small amount of water, so the white smoke could be from condensation in hot exhaust gases, particularly in cold weather.
In extreme cases, a head gasket rupture causes coolant to leak into the engine (often accompanied by a "sweet" smell) causing thick clouds of white smoke to spew. Coolant in the engine inhibits some performance, which may explain the lack of power.
I would suggest hiring a trained technician, like the ones at YourMechanic, to run a diagnostic to determine the source and cause of the white exhaust smoke, and recommend any necessary repairs.
Have a car question? Get free advice from our top-rated mechanics.
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%