We have a fairly new single-handle kitchen faucet with a separate pull-out sprayer. I don't know the brand. Yesterday it suddenly began making a loud, continual clunking sound whenever the water is running, and the water comes out of the faucet with a kind of "stutter." When we use the sprayer, there's no clunking and the water comes out in a normal stream. I read a few posts on this site about faucets clunking once or twice when they are first turned on, but ours keeps clunking from the time you turn the water on until you turn it off.
My DH appears to have fixed the problem. After posting my message about the clunking this morning, I opened the cabinet under the sink and discover a bunch of water! So something had been leaking and apparently letting air get in to the faucet. We discovered a leak in the connection of the sprayer hose to the pipe under the sink. DH tightened it up and the clunking has stopped.