I have a KFA170k dyna glo that will not adjust past 4psi. I have put an end cover and new filter kit and a rotor kit in. If i plug the air line at the nozzle it will produce 10psi or better. pressure for this unit is supposed to be 6.5 psi I also disassembled and cleaned the nozzle ,but had no change when I fired it back up.need help with a possible fix please?