u/Content-Lack3611

I have a hotsy pressure washer, it was originally the 16 hp 3000psi model but the previous owner swapped in a 20hp Honda motor and a 3 piston cat pump. It is tank fed. I’ve been having problems recently where the hose and wand seem to me shaking more violently than normal and it won’t build much over 1500 psi. This is very frustrating as it seems any time I work on it at home it works fine but when arriving to the job site it goes back to having the same issue. What might be some of the causes for this?