I have 2 problems. First, the kitchen faucet runs for a few seconds
then completely stops flow. it is a single handle type. I turn it off
and on again and it starts back up with a chug, chug, chug. Then it
runs fine for the rest of the time.

Second, my tub water pressure is very high, but the shower is very low.
Both are new fixtures installed by a plumber a month or so ago.
Thanks for suggestions!