How do I clean a Moen kitchen faucet diverter?
Minerals in your plumbing system begin to build up on the pipes and faucets over time. Eventually, if not removed, the minerals can restrict water flow to a trickle. This may explain the decrease in water pressure from the kitchen faucet. To repair the hose sprayer: unscrew the piece were the water is sprayed out. It should un-screw counter-clockwise. Hold it up to a light and look for any blockage. Soak in a bowl of white vinegar or CLR or Limeaway, etc. After some time soaking  replace the spray piece. Also unscrew the faucet aerator and flush out any debris that may have collected in the screen. To disassemble the faucet but after the water valves have been shutoff,  you will first need to remove the handle. Look for a set screw on its back. Once removed unscrew the top cap. You should now be able to pull the faucet cartridge out of the faucet body (probably with some effort). Look into the faucet body for any foreign matter that may have lodged in the faucet ports. Similarly examine the cartridge. If possible have an assistant slowly open the supply valves one at a time while you hold a cup over the faucet. You just want to allow a moderate amount of water to flow from the faucet to flush out any blockage. When re-assembled confirm that each valve is fully opened.