Are you sure it's too old? We had a 90 LeBaron that would kick out codes. We had to run the car at 2500 rpm's and cycle the air once, then let the idle come down slowly, then turn the key off, then on, off, on again, and the check engine light would flash a code. For example, check engine light flashes twice, (2). Slight pause, then flash on & off 4 times. This would be a code 24. It would then give us a explanation for what 24 means. I have a chiltons from that car still, if I can remember I'll try to look at it & see if 87 does the same. You may be right though, maybe 87's don't do this. I'm surprised it's not a TBI on it.