Plumbing - Pipe size and water pressure - yup, it's me again!?

It just may be that the junk you had in there has traveled to your faucets. Turn the water off and let pressure off by opening valve. Take the knob off and see what you find in there. It may have all kinds of junk in there. If there is still stuff in there you may need to turn the water on just a hair to push it out. It will come out where the knob was. If this does not work you can try blowing the lines out. If you go to a different size pipe the bigger you go the less water pressure you will have and the smaller the more you will get. the size you are talking about wont really make that much difference.