My SES light came on a couple days ago and I went to AutoZone and tried to pull the codes. Their scanner said it had a "Link Error" so I went to a friends shop and used his scanner and it said the same thing. I have put a new motor in the car as well as had the computer reprogrammed. I have all of the grounds hooked back up to the best of my knowledge. The SES light will come on for about 30 seconds and cut back off. Sometimes the car will have a little trouble idleing. I've checked the TPS a few times and it has stayed where I set it, .59.

 

I have the same problem on mine, except that mine is completely stock. I also noticed my speedometer drops when the light comes on. Im leaning towards a bad ground or bad ECM

 

Your problem is not the PCM.... it is the fact that the 1995 models have a 16-pin OBD-II ALDL connector, even though the PCM in the 1995 is OBD-I. That is why Auto Zone is getting a link error... they are trying to use an OBD-II scanner on an OBD-I PCM.

You need to find someone with an AutoXray OBD-I scanner, plus the interface connector for the 1995 ALDL. Or you need to pick up TTS DataMaster, or FreeScan software, and the correct interface cable.

Given your problem with idle, you might want to look at a dirty IAC valve, or a cracked MAP sensor harness connector. But you'll only be guessing without getting it on a scanner.