AC fan

The evaporator is freezing up. Yes, like a big chunk of ice, and that does not allow the air to pass very well. Check to make sure the freeze probe is correctly installed into the evaporator fins. The unit should be cycling the compressor on and off to control the formation of ice on the fins.

Make sure the filter is clean. the coils are clean and the evaporator is clean. Dust/dirt build up can create freeze ups easily. Don't overlook the possibility of low Freon after this long.

As others have pointed out sounds like maintenance time.

Thank you so much. I'll get on it and post back what it was.