I have a Kohler single-control faucet on my kitchen sink that I installed about ten years ago. Starting about a year ago, it would occasionally not turn on smoothly, but would spurt with a harsh thudding sound once or twice before flowing normally. It seemed as if something inside was moving to block the water flow momentarily with a water-hammer effect. This only happened upon turning it on, never while it was already on.
It slowly got more frequent and sometimes water flow would stop entirely after a spurt/thud until turning the handle off and back on again.
A few weeks ago, I finally replaced the valve cartridge with a genuine part (link) and also replaced o-rings in the faucet body.
This seemed to fix the problem. However, the faucet is already starting to thud and spurt while turning it on again. What can I do to permanently fix it?
During the faucet repair, I also discovered one of the shut-off valves under the sink was leaky. I think it had a very slight drip before, but started leaking significantly when I shut it off. Following advice I found online, I tightened the packing nut and it stopped dripping. Could this be related to the faucet problem?
Edit: To address the question from @Machavity, I don't see a visible part marking or recall specifically, but it looks like the "Forté" model with a sprayer as listed on the Kohler website (K-10416-BN).
It just crossed my mind that the sprayer has a diverter valve. The sprayer itself works OK. Could a failing valve cause this problem?
Update: After thinking of the sprayer the other day, I tested it. Most of the time it did work just fine, but a couple times it would shudder when releasing the spray button, and once the flow did not return to the faucet when I turned the sprayer off. I replaced the diverter valve today and it is working well at least for now. The old valve was noticeably worn, but didn't have any obvious functional problems.