How do you test the ignition coil on your 1994 Geo Metro?

Disconnect the distributor cap end of the coil wire and attach to an ignition tester. Attach the ignition tester to a good ground, away from any fuel lines. A good spark tester can be made from an old spark plug gapped to 0.200". Crank the engine and observe the tester for spark. If a crisp blue spark is noticed, the ignition coil is working properly. If a pale yellow spark, or no spark, is noticed, the coil is more than likely bad.