Losses power and eventually will not accelerate until cools off

Based on the age of the car, and a similar problem a lot of Ford products had, a good suspect might be a rubber hose connecting the fuel pump to the pickup screen inside the gas tank. On the Fords that hose would dry rot and develop little cracks that allowed air to be sucked up instead of just gas. That hose had a tight bend where the cracks developed very close to where the fuel level was at half-tank so the symptom was always the same. Fill the tank and only gas was surrounding the leak in the hose.