Hyundai Repair: Fuel Injectors, engine control module ecm, test light

Question
If I suspect a faulty FI circuit is causing a miss to occur, is there an easy way to diagnose it?  Can a standard test light be used to probe right at the injector?

Answer
You won't be able to test this properly with a standard test light; its resistance will be too low and can cause damage to the engine control module (ECM) if an attempt to use the lamp is made when the car is running.  Instead, there are lamps called noid lamps specifically made to substitute for the injectors.  To use, simply unplug an injector and plug in the lamp instead.  If the lamp flashes when the engine is running, you know the ECM is firing the injector and the wiring to that injector is okay.