Hi- I have a B7500 that I love and generally works great. Have recently been having some fuel issues. When the tractor is pointed downhill I will lose power and RPM's. Generally it will not stall, but comes very close. It will generally come back within ten seconds or so. Only happens on moderate to steep downhill areas. I've changed the fuel filter several times- thinking maybe the lift pump, but can't figure how the angle would make a difference. Any ideas?