Diverter issue ... or not?

[MCB]

I have a Moen two-handle kitchen faucet. One day, it went from working just fine to trying to send all the water through the sprayer. The water only comes through the faucet when enough pressure builds up behind the sprayer to force it to find another way out (and it overwhelms the sprayer head, too). I disassembled the thing and got a new diverter, but the new diverter, which is just a little piece of plastic, behaves the same as the old diverter, which makes me think it's not the diverter at all. Anyone got any ideas?

Possibly relevant: I removed the diverter entirely and ran water through the system, and, as expected, water came out both the faucet and the sprayer. So the diverter is doing something, but it's not clear to me what.

Thanks in advance!

 

[FishScreener]

Typically the diverter is a small pressure sustaining valve. It senses the pressure in the sprayer hose, and when the pressure in that hose drops if opens to feed more after to it to maintain the pressure at the nozzle.

You might have some kind of clog, between the diverter and the sink head.