Depress accelerator pedal fully to keep the electric throttle control actuator butterfly-valve wide open to maximize air intake flow.
Crank the engine and record the highest gauge indication.
Repeat the measurement on each cylinder (steps 5 - 7).
Always use a fully-charged battery to obtain specified engine speed.
If compression in one or more cylinders is low:
Pour a small amount of engine oil into cylinders through the spark plug holes.
Retest compression (steps 5 - 8).
If adding oil helps raise compression pressure, then the piston rings may be worn or damaged. If so, replace piston rings after checking piston.
If the pressure stays low, a valve may be sticking or is seating improperly. Inspect and repair the valve and/or valve seat. Refer to See: Camshaft\Specifications. If the valve and/or valve seat is damaged excessively, replace as necessary.
If compression stays low in two or more cylinders that are next to each other:
The cylinder head gasket may be leaking.
Both cylinders may have valve component damage. Inspect and repair as necessary.