UPDATE: Peerless faucets have a LIFETIME WARRANTY. Call 1-800-438-6673 for replacement parts, yours might be FREE.
How to fix slow flowing or bad sprayer flow on Peerless P299568LF, P299575LF, P299578LF. At first I thought it was a clogged aerator but it was the Diverter Assembly. Also clean out your sprayer (RP44125)!
The Diverter Assembly part number is RP41700. I bought mine here:
http://amzn.com/B004DQUD5Y
Parts manual in PDF from Peerless site:
http://www.peerlessfaucet.com/media/PartsDiagram/66474-PD%20Rev%20F.pdf