I have a drastic reduction of water pressure in my kitchen sink only. It is not the faucet itself as this is the second faucet in a row to do this. If I take the faucet off to check it or replace it then it works fine for a day or two but then reverts back to nearly no pressure. Is it possible that there is some sort of vacuum in this particular line?

Remove the aerator and see if screen is clogged with sediment.

Run water with aerator off for about a minute. This will help clear the line. Run both hot and cold water.

U may be picking up sediment from hot water heater. Do u drain off heater once a month to remove sediment from bottom? This will help prolong the life of heater.

Chuck