One of the more common problems with the VATS security systems in the third generation f-bodies is caused by a simple bad connection in the ignition cylinder. The problems start when the wires leading from the contacts in the cylinder to the VATS module develop an intermittent contact or a complete break. This can cause sudden failure to crank, either intermittently or permanently. Due to the nature of the system, manual transmission cars can t even be push started.
The first step is to check the resistance of the chip in the key with a multimeter. Write this value down, you ll be needing it later. Next, remove the panel under the dash and look for a pair of yellow wires coming from the steering column and leading to a connector a short distance away. Unplug the connector and with the key in the ignition, measure the resistance at the wires leading from the steering column. The reading should match that of the chip in your key. While the reading might match while the key is in the off position, it will probably change when the key is turned forward. If this happens, the problem is in the ignition cylinder or the wires leading to it. At this point there are two options: Buy a new ignition cylinder and for alot of money or bypass the system for less than a dollar.
To bypass the system you ll need to buy a resistor with a value matching that of your keys chip at any local electronics store. The easiest way to install this resistor is to cut the wires leading into the column about a foot from the connector. Take this section of wire, strip the ends and solder the resistor in place. Take this section of wire and resistor and simply plug back into the connector under the dash. The VATS module is now fooled into thinking that there is always the correct key in the ignition. Although this does render the security benefits of the VATS system useless, if increased security is desired, the resistor can simply be unplugged, leaving the car disabled until it is reinstalled.