Low pressure upstairs

My husband has just run new water lines throughout our entire house. The water runs fine, but we are having a bit of problems with water pressure in the cold line only. Our kitchen sink and 1st floor toilet have excellent pressure, but our 1st floor lavatory sink, 2nd floor lavatory sink,toilet,and bathtub have very low pressure in the cold line. And suggestions on what it could be or how to fix it?

Remove the aerators from the tips of the spouts; with the aerators removed open and shut the isolation valves numerous times to free up any debri.