IF you are not sure of where the click comes from, put a stethoscope right on the injectors when you turn the key on. Poor mans stethoscope is a screw driver touching the injector and the handle stuck in your ear.
My gut feeling is, (especially after you mention mechanic messing with the ignition) is the ECM not getting power. I need to go look at some documentation on what feeds the coil, but what I will want you to do is hot wire the coil, and see if it starts. I just can't tell you which wire to connect to the battery. I won't be able to look it up till tonight.
BTW: I assume that the engine cranks every time you hit the key, correct?
