Hot water side of the faucet runs, doesn't have much pressure, and hardly gets warm, let alone hot. The sprayer was releasing hot water, or at least hotter than the faucet, and now is just luke warm. There is some knocking too. The kitchen has always taking a too long to get hot water, longer than it should and a plumber told me in the past that it is just because it is the furthest faucet from the hot water heater... it is maybe only 30 feet from the hot water heater... that does not seem that far to me. Just to get warm water takes at least 10 minutes. The pipe coming out of the hot water heater is hot, and we raised the hot water thermostat to about 130 -140 a few days ago. The water was really hot for about a day, still took awhile to get hot, but was hot, now is colder than it has ever been. HELP... :confused:

Have you checked the heating elements in the heater?

Well, not specifically, but there is hot water in the bathrooms... so the assumption I had was heating element was fine. It is just the kitchen that has the problem.

OK! Let's assume the water heater's functioning. This puts the problem squarely in the hot water supply or the kitchen faucet. My guess is that you don't flush your heater out on a regular maintenance schedule and mineral build-up from the heater got sucked up into the kitchens hotwater line when you made a draw.
The solution would be to shut the water off under the sink and open up the faucet. Check and clean the inlet ports of the cartridge and before you reassemble turn on the hot water to flush out the supply. You should have a strong stream coming out of then open faucet when you do this. If you don't flush your heater let me show you how. For long life and fewer troubles you should keep your heater clear of mineral build-up by flushing on a regular schedule. Attach a hose to the boiler drain at the bottom of the tank. With the pressure on, open the boiler drain and let it run until the water runs clear. You will see a spurt of red,(rust) followed by white grains,(lime or calcium carbonate). This shouldn't take more then a few minutes. Do this monthly to keep it clear. Now flush out your hot water lines on ALL fixtures. Now pull each aerator and clean the screens. Be sure you put them back togather the same way you took them out. Don't forget to flush it out every month. Your heater will thank you for it. Hope this helps, Tom

Ok, I am going to try this afternoon to get this done, including the flushing of the water heater, as you are correct... I have not been doing that on a regular basis. So cross your fingers... and hopefully all will be good. Thanks for your response...