not sure what i am missing but need assistance. I have a Genie GS1930 - GS30P unit that will not raise with someone in the basket. I have checked the main system relief pressure and it is 3500psi. I have checked the lift system relief pressure and it is 3500psi. I have put a gauge tied into the manifold and the pump is putting out 2800 psi when putting load on the hydraulics driving into something solid. Problem is i can get in the basket and unit will not raise more than 6". I use the ground controls and the unit sometimes will not raise more than a ft but other times will go all the way up. the manual shows the unit requires 2500 psi. Am I missing something or over looking something. Any advice will help.