I messed with these stupid things for a long time and know that year series thru and thru.
start off by turning the ignition to "on", watch the lights and make sure there is a bulb in the "Check Engine" indicator.
now drive the car and/or allow it to reach normal operating temperature. Keep an eye on that Check Engine light. The on board diagnostics on these cars (OBD1) are pretty nice because you do not need to buy a code scanner to read the trouble codes, all you need is a bobby pin or a piece of wire that you can jumper the two pin green service connector located under glove box. With the ignition on and at operating temperature placing a jumper between the two wires will cause you're "Check Engine" indicator light to blink a series of blinks that coincide with the trouble code number. A list of these codes can be found online, or a Haynes/Chilton's manual.
That is usually the first thing I look for in those cars. If the light is on, chances are it has been on for a while and is a sign of neglect. It also causes the computer to change fuel and ignition maps to a "Limp Mode" state that can kill your catalytic converter, foul your spark plugs and much more if it is ignored for too long.
You really just want to find one that has never been "Modified" in any way. If the car appears to be lowered.. run! if there is anything other than black split loom on any electrical harnesses... RUN! if there are any body kit pieces on the car or ANYTHING that appears to be aftermarket...
well you get the point.
post pictures if you want.