Intake Manifold Vacuum Test

Run the engine until normal operating temperature is reached. Connect the Vacuum Pressure Tester 164-R0253 or equivalent to the intake manifold. Run the engine at the specified idle speed.
The vacuum gauge should read between 51-74 kPa (15-22 inch Hg) depending upon the engine condition and the altitude at which the test is carried out. Subtract 4.0193 kPa (1 inch Hg) from the specified reading for every 304.8 m (1000 feet) of elevation above sea level.
The reading should be steady. As necessary, adjust the gauge damper control (where used) if the needle is fluttering rapidly. Adjust damper until needle moves easily without excessive flutter.