Diagnosis
Surging or weak pressure is a classic sign that the machine isn't getting enough water supply. It's trying to pump faster than the water is coming in.
How to Fix It
Start at the source. 1) Make sure your garden hose faucet is turned on all the way. 2) Check for any kinks in the garden hose itself. 3) Ensure the inlet water filter (the screen inside the hose connector) is clean. Unscrew it and rinse it. 4) Try your garden hose without the pressure washer attached—if the flow seems weak, you might have a clogged hose or a low-pressure supply issue. The machine needs a good, strong flow to work right.
If That Didn't Work
The nozzle on the spray wand could be partially clogged. Unscrew the black nozzle tip and look through it. If you see any sediment or debris, poke it clear with a thin, stiff wire (like a paperclip). Don't use anything that might scratch the orifice.
Heads Up
Always use the high-pressure hose that came with the machine. A standard garden hose on the output side can't handle the pressure and will cause issues.