The sprayer for my single handle Kohler faucet is working oddly, and refuses to stay fixed. The original problem was that the spray would start strong, then after 15- 30 seconds would peter out to a very low flow. It never stopped working completely. First I replaced the head, which seemed to fix it at first. Then after using it a few times it's acting the same as before. So I removed the diverter and soaked it in vinegar water for 2 hrs (also replaced O rings while the spout was off). I was so happy that it worked perfectly. We ran it long enough that it would have pooped out if it was going to. Then the next day the spray started petering out again. Now I wonder if I should replace the diverter. I did replace the diverter about 3 years ago, but then there was no flow at all from the sprayer. I'm not sure that is the problem now.

Any ideas?

If you are in a high mineral area as I am, this problem will just go on and on until you do something to prevent deposits.
I used to soak in vinegar too, and it lasted only a short time.
I can't address the Kohler sprayer.
Just want to say I sprang for an expensive water softener (Pelican brand) that uses no electricity and no salts. It's small in diameter and light, and needs no maintenance. It comes with a water pre-filter that needs a new insert every year, and anyone can change it. Rather than exchanging salt ions, it crystallizes minerals, so they don't stick to anything. Pays for itself over and over.

I wondered about that because there is some buildup around seams, but it seems like it would take a while for that to cause a problem when I've just cleaned the diverter with vinegar, etc.