New to me Miller Condor with Raven Envizio Pro has pressure of 100 with agitation on, boom off. Boom on pressure starts out around 40 or so then gradually drops to around 25. I try to speed up it doesn't increase. New hoses and flange gaskets. No visible leaks. 15 inch wet boom spacing. 8005 at 17.5 gpa. Control valve? Pump impeller?