A flow bad flow restrictor would definitely cause the issues you are seeing. Easiest test i do is simply remove the restrictor and temporarily put a shut off valve in its place . And with pump OFF and inlet on, note what the water pressure is. Then open the valve fully. Pressure will drop and turn the booster. Slow begin to close the valve staying within the max rated psi of the unit. If the pressure exceeds the base test psi with out the valve being fully closed it’s most likely a bad valve. If you able to close it fully and pressure is the same then issue is up stream probably pump related. If your unit has a set screw adjustment screw make sure that is also set properly and that there is no blockage before the pump. Also try not to have too long of line to the pump if running 1/4 line otherwise consider upping it to 3/8s.