A8: General Engine Diagnosis Cylinder Leakage Test Head Gasket Failures In-Cylinder Compression Injector Pulse Balance Test Noise and Vibration NVH Relative Cranking Compression Test with Fault Test Engine Coolant Temperature ECT Sensor Vacuum Gauge Readings Vacuum Gauge, Bad Valve Guide Vacuum Gauge, Faulty Valve Vacuum Gauge, Head Gasket Leak Vacuum Gauge, Retarded Timing Vacuum Gauge, Retarded Valve or Ignition Timing Vacuum Gauge, Weak Valve Springs Verify Engine Operating Temperature