you can test the injectors (remove them) with a 9V battery and a couple of speaker wires. Although i've never done it, i've heard the process is pretty simple.

you can also see if you can hear the injectors while the car is on.
leave the car idling, put a long screw driver up to an injector and put your ear to the end of the screwdriver. See if you can hear the injector ticking, then move onto the next injector.