kubota hydraulic issue

Hi everyone have a bit of wierd prob with KX161-2 dozer ,swivel,and swing are all slow all other operations are working normal this is the wierd part sometimes itll work from start up and all day or sometimes start and its slow all day lol one minute there next not ive checked all relief valves and pump pressure it seems fine looking at the hydraulic circuit chart ( not very good lol) at pump one and two inlet it looks like a switch of some sort that supplys low pressure to turn both pumps on i heard it has somthin to do with fuel consumtion why run both pumps when not needed i guess any help greatly appreciated and thanks in advance

kubota hydraulic issue