Ignition Coil Resistance (Externally Mounted)

Remove coil connectors and secondary coil wire. In test "A", use high ohmmeter scale. See Fig 1 . Resistance value should be very high (infinite). If resistance is not infinite, replace coil.
In test "B", use low ohmmeter scale. Reading should be approximately zero ohms. If resistance is not approximately zero ohms, replace coil. In test "C", use high ohmmeter scale. If there is no continuity, replace coil.

Fig 1: Testing Ignition Coil Resistance (External Coil)

Courtesy of GENERAL MOTORS CORP.