Not to hijack the thread, but I'm also having trouble with our
Moen kitchen faucet. It's a single-handle one with a pull out
wand that can be switch to spray or single stream. However, a few
months
ago, after perhaps 5 years of service, it has come to like the spray.
That is, it is on spray from the start when turned on, and it's nearly
impossible
to get it switched to single stream.

Is this also a cartridge issue?

TIA

Ed