So, I have a running problem with my car. It's a 1990 fox mustang vert with a 2.3 four banger/auto trans. Runs super rough and is blowing black smoke out the tailpipe. Obviously running rich. Originally it did this intermittently but now runs like this all the time. I threw a new MAP sensor on because I had a new one lying around. Did nothing. So, here's where I'm stuck. Tried getting codes out of it but it doesn't seem to be working correctly. Used a jumper wire across the test terminals (yes, in the correct slots, Pin 2 and the STI connector.) But the check engine light does not flash when I turn the key to run, and with a test light on the number four pin the test light is lit up constantly, no flashes, no nothing. What is happening? Is my computer junk? Am I doing something wrong? I'm following directions from manuals and online instructions. If anyone knows what might be happening or has any advice for me, it would be MASSIVELY appreciated. Trying to get the car ready to be sold this summer and it's not gonna sell running like this lol. I am used to working on carbureted Mopars so this is new territory for me. Thanks for reading y'all.