If you have a pump running unusually rough then check the coupler to the electric clutch and if everything's OK you can take the valve cover off and push on the stem if liquid comes out the diaphram is ruptured .
The diaphram takes air 15 psi roughly or 1/3 the pump pressure . You should check before using your sprayer along with the tires . Check psi and only takes a very quick shot of air . The repair is very simple just remove all the nuts and bolts and pull the diaphram out and replace it with a new one .
Pick of the diaphram
The dark blue area in center of pick is a hole .Without the counter air pressure to off set the pump operation it will run noticeably rougher and should be taken to the mechanic right away . The extra vibration will wear out hoses against the frame really quick.