Don’t need help, sorted it now. Just creating a thread for people needing help in the future.
I experienced a drop in pressure while I was working. My machine felt like there was cavitation in the pump. Vibration coming through the hose and gun.
I thought unloader had gone bad but supplier said to check it was still bypassing correctly. It was and they said suction valves were likely the cause.
Started it up and there was no issues so thought it was just debris that had got by my filter and had worked loose.
Done another job, pump gave up an hour in to the job. No pressure coming out of the gun, hardly any flow.
Went to my suppliers and they took the auctions valves off and sure enough one of the valves had broken.
Hopefully helps someone who has issues with a substantial drop in pressure and trying to figure out what went wrong