Older Landa Electric pressure washer pulsating

Hi everyone…first post here. The pressure washer we use at our school district bus garage has suddenly started pulsating/surging. Intake and outflow both check out clean. It is a Landa on 220 with 2000psi pump and a Baldor motor. Where do we start to troubleshoot this issue?
Thanks for any help

Try you local Landa dealer or small engine repair shop

Test the spigot on the building, are you getting enough gpm flow out of it?