DIAGNOSIS This is almost always an issue with the inlet water supply or a clog in the system, not the pump failing. The SPX3000 needs a good flow of water to build pressure.
FIX 1) Check your garden hose for kinks and make sure the faucet is on all the way. 2) Remove the inlet water filter screen (where the garden hose connects) and rinse it clean. Mineral deposits here are a common culprit. 3) Check the tip on your spray wand. Remove it and see if there's debris lodged inside. Soak it in vinegar if it's scaled up. Try one of the other colored tips that came with the machine. 4) With the machine OFF and water flowing, squeeze the trigger on the wand to flush any debris backward through the system.
IF THAT DIDN'T WORK The unloader valve (the part that regulates pressure) might be stuck open. This is a more involved fix requiring you to open the pump housing, but it's often just gummed up with deposits and can be cleaned.
HEADS UP Never run the machine without a tip in the wand. It bypasses the pressure control and can damage the pump. Always start with the black (soap) or widest-angle tip to confirm flow.