I have a 1993 Saturn SC1 with 200K miles and two problems. I can run the AC on a hot day for nearly an hour, then the air flow fades away even though I can hear the fan still running. If I turn it off for a while, I can then turn it on again, and it runs fine for a while but then fades again. On a cold, rainy day, even though the fan blows fine out the dashboard vents toward me and my passenger, there isn’t enough air blowing out of the vents below the windshield, which fogs up so I can’t see.
Your evaporator could be icing up. Instead of turning off the fan, just turn off the ac compressor until the air comes back.
You may be a little low on refrigerant.