Single handle kitchen faucet, cold water flow reduced

[concernedbiological]

Hi

Have a single handle Kohler kitchen sink faucet

When handle is down/towards the hot works fine

But up/away for cold the stream is a trickle

Worked fine until the valves were shut off to diagnose a separate issue. Valves were opened back up and now this behavior

Any ideas what I can check?

The only other valves below the sink is the valve for the dishwasher.

Thanks

 

[breplum]

we start by connecting flex to angle stops and run into a bucket to confirm you have perfect flow.
Next is working way through the valve.
you may have a clogged port and replacing cartridge after confirming flow at the ports.