I got same problem like the other people here BUT I know it is not the faucet. I branched a new line to a sink that I moved and as long I do not turn the faucet fully on it runs lightly. I disconnected the flexible hose under sink to see where the problem is coming from and at the moment I turn fully on the valve there is bang and water shuts off immediately and will not run at all. If I wait for a while the water comes back at full pressure again but again as I turn the valve on fully it shuts off. It seems like it has to do with vacuum or something in there! Would anyone know the culprit why is that?
Thanks.

What kind of the "flexible hose under sink" do you have ? It sounds like you have the type of water connectors that shut off water automatically when they detect demand for large amount of water. Do they have about 2" of solid end ? Back to you. Milo

I agree with Milo. Sounds like your flexable lav supplys are the culprit, or could be the washers in the stops. Try this. Disconnect the flex supplies from the actuall stop (shut of valve) and see what kind of flow you get straight out of the stop. Make sure to have a bunch of towels and a bucket handy to keep the water under control.

I do have those flex hoses connected but on the other one it works fine. I'll try tomorrow again by switching the hoses from the ones where it works. Actually, I do get same banging and stopping result on the tub spout, as long is not fully open it runs but stops once I fully open it.
Thanks much.

They look like this... See the left end with "FloodSafe" device...

Yes, that's what they look like. I do not understand what's the purpose of it! I think it is ill defined to protect. If you leave your faucet running then you know about it, where else it can leak between the sink and the valve(?? ), do the old type flex pipes broke so much that they have to replace them with this..

These are called "Flood Control" water supply lines. Home Depot sells them. Their purpose is to stop water when water supply line bursts while nobody is home. Good idea - but they don't work exactly how they should. We stopped using them few years ago. We have found out they cut off water flow even when there is no pipe burst. This is true especially at washing machines where water flow is high and continuous for longer period. We also experienced lot of problems when installed on toilets. Interestingly enough, when one connectors shut water flow, it sent water hammer through the plumbing system, shutting off other Flood Safe connectors in the house.

Moreover, Flood Save end has series of filters in it. These filters-like inserts are responsible for slowing water flow due to debris traveling through the pipe and accumulating in them.

I suggest you replace them with regular water supplies. I am sure that will solve your problem.

Hope that explains. Let me know how you did. Back to you. Milo

Yes I did took them back and got the once without that nonsense. It works fine now. But, my bath tub spout still does not provide full output and it shuts off if I open it fully(?). I do not hove connected water heater so I do not have water coming into the hot side of the mixer but still, should that cause why the cold water does not work properly? It stops running when I open it fully and then it does not want to run any water for awhile or very little (! ).
Thanks.

Not 100% sure but I think it is related to lack of hot water flowing through the faucet. Today's faucets have temperature and pressure balancing device built in. They need pressure from both, hot and cold side to function properly. Connect your water heater and test it. Let me know how it went. Back to you. Milo

I need a bit more time for that so it will not be right away but I will let you know.
Thanks much.

Do you have a washing machine hookup? If so, simply hook a washer hose between the hot and cold of the washer supply valves and turn hot and cold on. This will pressurize the hot side of the system. Now go and see what the shower faucet does. Should get good flow.

I had to find my FF connector since I did not have wash machine hose but I used garden hose. It did not shut off and it worked but it seemed like there is not enough pressure coming out of the spout. Hopefully it will work once hooked up.
Thanks much guys.

Yes, pressure should increase once you get the actuall water heater piped in. Take care.