How can tell if fuel injectors are bad in 1990 300zx?

To determine if the fuel injectors in a 1990 Nissan 300ZX are bad, listen for a clicking sound while the engine is running, which indicates they are functioning. Additionally, check for poor engine performance, such as rough idling, misfires, or decreased fuel efficiency. You can also conduct a resistance test with a multimeter; if the resistance is outside the manufacturer's specifications, the injectors may be faulty. Lastly, inspect for fuel leaks around the injectors, which can also indicate failure.