Thanks for the input Herman and wildbill , sorry I didnt leave more info . 99 National Tradewinds 36'6".Autometer gauge has 1/8" fitting on back. Iran at 1100 PM for about 5 minutes before it started dripping . put it back together and gradually got to 50 psi but that seems too slow. cat 3126 ,fresh oil ,no leaks. could manifold be plugged on the outlet I used. Dash gauge responds fairly quick but it's just a low or high gauge . ( reason I went with a mech.gauge.