Second cylinder not firing...

[A18]

So my car isn't firing on the second cylinder. The injector for the second cylinder won't fire, but the injector works fine. I switched the injector from the first and second cylinder and it made no difference, the second cylinder still didn't fire so I know it's not the injector. We checked the connector with a noid light and the light lit up on all the cylinders other than the second one. My buddy got a new connector from work and we replaced that, and it made no difference.

I asked my other friend about this and he says its either the PCM (aka ECU) or a short in the wiring. I can't find any frays or breaks in the wiring, so I'm thinking its the ECU.

If it is the ECU, do I have to replace the ECU or is there anyway to fix it? Can I use any ECU from any R32 gtst, or did the ECU undergo any changes in 92+ to match the rest of the changes (headlights, grey gauge cluster, etc) making it incompatible with the 89-91s? This is for a 1990 skyling gtst btw.

Finally, does anyone know what a used hcr32 ecu goes for these days? PM me if you have a working one for sale, preference given to locals and lowest priced, obviously.

Thanks for you help guys!