Ted, Check the 2 rubber lines coming off of the regulator. One of them is a atmospheric pressure line which goes from the bottom of the mixer to the trim valve on the regulator. There is another rubber hose down below on the regulator that connects to the top side of the mixer (black 90 fitting). Pull these one at a time and see if there is a change in your issue. Make sure they are not crossed also. One is a vacuum and one is atmospheric. Hope this helps.