<< I need a nickel's worth of free advice for a plumbing expert. >>
Here's $.02 worth, since I'm no expert..
FWIW. my experience with PF kitchen faucets has been to simply replace them
after 18-24 months when they go belly up. Now using Kohler because they're like
the energizer bunny, they just keep going...
Moen seems to be one of more repairable brands in our area. Good stock of
cartridges and stuff at tye box stores. HTH