I just bought a 89 Firebird with a 2.8L engine...
It was pretty hard to get it started...I was never sure what the problem was...I though it was gthe starter because the car turned ON (the radio + A/C + gauges work) but it doesnt turn over and crank on...it doesnt even click or anything...At first it did crank and turn over after messing with it for a while...but latelly i have not been able to at all...
I also noticed that the the car turns ON even without the key on the ignition cylinder...it rotates as if it had the key in it...but does not crank on

Last time I got it to turn on it runned great...the tranny shifts perfectly and only has 80K miles on engine...after the engine warmed up...the car started perfectly time after time ( i though the problem was fixed for good)
But after letting it sit there overnight...It would not crank again...idk what to do...Please HELP!!

I though maybe the Vats went off since cylinder is messed up but the engine did turn on when i messed around with it last time...and the light is not on the gauge...but i think its still a posibility

 

Your best bet is to start probing wires with a voltmeter. Probe the power wire leading to the soleniod while a buddy turns the key. ( Be carefull ! ) If the soleniod gets power when the key is turned than the VATS system is not causing your "no crank" issue.

 

Does the security light come on? if there is a vats problem the sec. light will come one and stay on when you turn the ignition switch on.
if it will start with no key at all the the cylinder is probably broke and i would bet there are resistors soulderd into the 2 wires coming from the key switch that connect to a small connector (2white wires wrapped in orange) oh wait you said firebird .... the wires may be different colors. but anyway :watch for the security light: