You need to use your flow gauge to check for proper flow. If the flow is too high, it will definitely cause the pool cleaner to not move properly. There are a few more things that you will want to check. Make sure that the diaphragm does not have damage or wear and tear. If it does, replace it. Backwash your filter and empty the pump basket. Obstructions or debris in them can cause lack of movement. Check for air in system. Raise individual sections of hose about the water and look for cracks or leaks. If the water level in the pump basket drops or you see excessive air bubbles in the pump basket or coming from the return lines, there is air in the system. Check hose connections, tighten all fittings at pump, and check gasket in pump basket for wear.