Agree try strainer, make sure line clamps tight, etc. How cold is it, problem with slightly slushy water? Pump slightly worn and needs a tweek adjustment. On my Sureflo the screw for that on front of pump. Turn a little makes big diff, to increase or decrease pressure. All else fails most pumps have rebuild kits I think the Shurflo does I know. Reason vanity doing something diff. than others is it's relatively location with pump location in the sytem more than likely. Hope it helps.