Check the codes to see if you have a 214: CID circuit failure which would indicate a bad camshaft sensor. Also contains code meanings. Most of the codes don't cause the Check Engine light to come on:
Can be done with a paper clip, but I recommend you get one of these:
If the sensor is bad, run your finger along the bottom of it to see if it's wet with oil. If so, you will need to change the seal behind the sensor as well....
Camshaft Sensor (Duralast) F134 $38 Autozone
Camshaft Seal (National) 1213N $8 O'Reilly
You can download this file which is a shop manual in PDF format covering the '89 engine. Your engine will be virtually identical. You will need the Acrobat Reader:
www.dropbox.com