You can stretch the time requirements if the reason you moved out was due to military or foreign service orders. The maximum stretch is 10 years, meaning you would have to have lived in the home for 2 years of the past 15. That seems impossible given the time line you described (moved out 16 years ago).
Otherwise, there are no special capital gains tax breaks for selling second homes or any other kind of asset or property, other than the fact that all long term capital gains are taxed lower than regular income. The tax code is set up to encourage residential home ownership, and does not give the same breaks to landlords or vacation homes.
