Remove the faucet handle and trim. Close of the check valve stops on each side of the valve body with a flat screwdriver. Remove the balancing spool and Moen cartridge. Look for and mineral buildup in side the faucet and on the spool or cartridge. If there is buildup on the spool and cartridge, place them in a large bowel with a cup of vinegar and a teaspoon of baking soda. The solution will remove the buildup in a few minutes. Replace the Moen faucet parts and test the faucet. If there is buildup inside the faucet body, use a wire copper fitting brush to the remove the minerals from inside the spool and cartridge tubes of the faucet body. Turn the stop valves on just a little to wash out the debris before reinstalling the spool and moen faucet cartridge. If the is is still no pressure on the one side or the other, turn off all the water to the house and remove the check valve stops, clean them as well and the inside of the faucet. If all else fails, replace the stops, spool and cartridge. Beyond that, the water supply lines may need to be flushes with the same solution.