Chilkoot

I've got a '93 with about 140k, and I've noticed that I have a small amount of white vapor (steam or white smoke, can't really tell) coming out of the exhaust. It's only just enough to be visible out of one of the sideview mirrors at a time at idle, depending on the wind. It disappears (can't be seen in mirrors) as soon as I start moving at all, but it's there every time I drive the car.
I drive the car 6 days of any given week (maybe 25-30 miles, short trips)and the temperature does swing 15-20 degrees here from day to day, but is that enough to keep creating that much condensation? Every time I'm at a stoplight I see it, even warm, but I only drive maybe 1 to 2 miles at a time after the engine has warmed up, and make only maybe 2 seperate trips in any given day. It used to do the exact same thing when the tank was almost empty, but I try to keep it between 1/4-1/2.

Fluids are still full, have been for the last 2500 miles. PS is not an issue, intake hoses swapped and the ACV feeding back to itself a la the DIY thread picture, fixed my idle problem too. Oil is Mobil1 5w-30, maybe 6 months old, 2500 miles (though needs a change, starting to change color slightly). Coolant temp sensor has not been changed yet, could that be an indication of running rich? I estimate 15-16mpg.

thanks for any suggestions.

Should I be worried that it's not steam?