Car trouble (1994 toyota supra)

[Whipper Snapper]

I have a naturally aspirated 1994 supra. Unfortunately, I ran into some car trouble the other day. My father and I have tried a little bit of everything, but can't figure out the problem. I was wondering if any of you car buffs could maybe help diagnose the problem.

Car was running fine, when all of a sudden (thursday), it just died. When I started it back up, a bunch of black smoke came out the exhaust. The car does not idle, but will die if you don't keep your foot on the gas. It feels like the car is in "limp mode". The car has very little power, and trouble going through the gears because of that (it's an automatic). Still plenty of black smoke.

We figured out that black smoke means too much fuel. We reset the ECU, have looked into whether or not it could be a catalytic converter problem. My dad has hypothesized that fuel is only getting to a couple of the cylinders and the rest aren't firing- hence the rich mixture (black smoke) coming out of the exhaust as raw fuel is being dumped in the motor but not igniting.

It can't be just one fouled plug (would have to be multiple). I know what it's like to have a cylinder miss. It feels like three cylinders aren't firing here. Dad also thinks it could be the fuel filter- like it being clogged. I don't see how that can be, as the black smoke would seem to indicate too much fuel.

Anyhow, there's the problem. I'm thinking the ecu itself might have to be replaced or maybe an O2 sensor went bad. I would love to think it's an easy fix like replacing the fuel filter, but I'm not that optimistic.

Let me know if you all have any suggestions...