The water flow through the faucet and spray periodically shuts off. Sometimes if I pump the spray while the water is turned off, then turn it on, the flow begins again. Sometimes it doesn't. I'm going crayz...

Sounds like you have trash that has got into the supplies or valve body and areb blocking the inlet ports. Solution is to shut the water off and open up the faucet. Remove the cartridge and check the inlet ports. Now turn the water back on for a moment to flush out the supplies Reassemble and test. Good luck, Tom

Have you repaired or replaced this faucet? Do you know the name of it? Have you checked the diverter?