Camshaft position sensor location

At the right rear of the engine under the intake manifold and to the left of the oil filter. You will probably need to go under the car to spot it, it's the sensor with a three-wire connector arranged vertically. But you can take it out from above. It's held in with a single bolt with an eight MM head located just above the sensor. Un-clip and remove the electrical connector. Unscrew the bolt with a socket wrench & extension bar. Wiggle and pull the sensor out.
here is a picture.

I have a 96 cavalier and it doesnt get fire to the plugs. I asked another mechanic and he said it could be crank sensor or the ign module. i thought the ign module was a fuse or like a switch but in fact it is like a plate the coil paks sit on. my question is on this; how can i tell if the module is no good?