Hot water flows slowly but then turns off?

Do you have full cold water flow? If you do not. Remove aerator and clean or replace.
If you have have full flow cold water but do not have full hot, you have a blockage in the hot side. Turn off hot water stop valve. Remove hot handle and stem. Place cloth over hot port and turn on hot water stop valve briefly to flush.

If that does not fix the problem, the blockage is in the hot water stop valve and it will have to be replaced.