I installed a Price Pfister kitchen faucet model low water pressu

I also needed to remove the "hidden" flow restricters from my Price Pfister Parisa Kitchen Pull out faucet. The hot water side had never flowed the same as the cold side. Now both sides are flowing the same as should have been all along.

Check the screen if it is clogged. That can slow down the water flow.

That faucet was discontinued some time back for the one you ordered parts for and the only way to get the part if it is still available is to know the part number. Now if you have a plumbing parts house in your area that specializes in faucet parts they may be able to match up the old part if you still have it.
If you can find the part number for the faucet you have then the part may still be available from Price Pfister.

Call price Pfister at: 1-800-PFaucet
They have excellent customer service and can point you in the right direction.

Remove and clean the Price Pfister aerator. Turn the water on after you remove the aerator and check the flow-rate. Many new Lavatory and kitchen faucets are now equipped with Eco friendly water saver aerators. if the flow is normal without the aerator, the faucet is OK. if you want more water flow from your lavatory faucet, you will need to buy one of the old style high flow aerators from your hardware store. If you remove the aerator and still get low pressure from both hot and cold faucets, you may need to replace the faucet. Call the Price Pfister warranty phone number that came with your faucet.

try un-screwing the screen on the end where the water comes out. Could be clogged

Call Price Pfister at 800-732-8238 - open Saturdays. They just helped me!

it souns like a factory flaw in the piping or whoever hooked it up, over bent or kinked the line

Three possible reasons for low pressure. 1. faucet cartridge has debris in valve body. 2. aerator has debris ,just unscrew and clean out. 3. Water valves under sink are not opened up. hope this helps

You more then likely replaced the diverter washer backwards. There is a washer/gasket that has multiple holes (2 or 3) and it is probably just rotated 180 clockwise (or counter).

There are very few moving parts in a faucet so this should fix it.