Karcher 2500 PSI Pressure Washer "attendance allowance rate" Questions

I have a dewalt 3750 pressure washer, when I pull the trigger on the spray wand the engine dies I worked at a tool rental center while attending college and learned many tips and tricks about Dewalt ...

Low Pressure with no hose attached, pressure is good, attach hose without wand and pressure drops 50%. Have had pump apart 10 times, have checked bypass valve, have even removed bypass and filled ...