All of our faucets have sufficient water pressure except the one in the kitchen. It is one of those with the sprayer in the faucet so you can pull it out and hit a button and it will spray. When I hit the spray button, the pressure seems fine. But when I revert back to normal flow, it often has very weak pressure, while a bathroom faucet only a few feet away is perfect. I looked under the sink in the cabinet and saw connections to the dishwasher, but the connecting hoses to the sink were long and coiled around quite a bit. Does anyone have any suggestions on how to troubleshoot this problem and fix it?

It sounds like you have some debris clogging the aerator. The aerator should unscrew and hen you can remove the screen and clean then then replace, also check the water restriction orifice.

Turn off the water and remove the hose from the faucet. Have someone turn on the water to see if there is good pressure in the hose to the faucet. If so, there is a problem with the spray head.

Do you have hard water? We do, and our kitchen sprayer hose had really gotten anemic. Very little water was coming through. We soaked it in vinegar overnight, and voila! Water pressure again!

The faucet probably has a low flow device in it and switching to the spray is similar to an adjustable garden nozzle.

The screen in the regular outlet is most likely clogged. You unscrew it from the faucet, and clean out all the sand, and other debris. Should work fine.