Poor engine compression or air leaking out of the cylinders can be measured to determine if your engine mechanical components are working correctly
Good leak down test
Failed leak down test
The “Leak Down Tester” is connected to a fitting in place of the spark plug. Using Shop Air, the gauge will show how much volume of air is leaking out of the cylinder. This engine idles Ok but shows a misfire and lack of power under load.
Replacing spark plugs, wires or engine sensors will not fix this problem. Diagnosing the problem effectively first will save cost & time
