When we squeeze the handle of the side sprayer, only about half of the water flow is diverted through the sprayer. The remainder continues to flow through the faucet. I replaced the cartridge but the problem remains. Is there another part within the faucet that handles diversion of the water to the side sprayer?

The plumbing shop suggested that I try replacing just the o rings on the diverter (they were quite worn) but this did not completely resolve the problem. I called Price Pfister The plumbing shop suggested that I try replacing just the o rings on the diverter (they were quite worn) but this did not completely resolve the problem. I called Price Pfister

there is a small diverter part that fits inside the faucet, it is located under the spout. you must remove the spout to get to it and see it. these are quite common. am not sure if your hardware store will carry this, but they should.
be sure to grease everything with non silicone based faucet lubricant, your faucet will work good as new.
if you called Price Pfister, they will tell you the same and hopefully send you a breakdown of all the parts of the faucet. there is a small diverter part that fits inside the faucet, it is located under the spout. you must remove the spout to get to it and see it. these are quite common. am not sure if your hardware store will carry this, but they should. be sure to grease everything with non silicone based faucet lubricant, your faucet will work good as new. if you called Price Pfister, they will tell you the same and hopefully send you a breakdown of all the parts of the faucet.