Hyundai: 95 Accent transmission

While running the vehicle for awhile. When i come to a stop light the car
does not have any pick up no matter how much gas you try. I put the car on
the low gears and after several minutes it will go back to normal. This
only happens when i stop.

Does the transmission shift through all the gears normally?
Does it start out in high gear and never shift?
Can you tell if the engine is running correctly?
If you shut the car off and restart it, does it accelerate normally?