Nabaness

I'm not even sure where to begin to be honest...

There's a knock around the #4 cylinder when it does decide to run, but now it doesn't stay on and it's a painful to start. It's backfiring, missing terribly, and we just timed it. New computer in it, new distributor, new rotor and new wires (Yes, they're all going to the right cylinders) new spark plugs.. When it did run, it smelt terribly of gas out of one exhaust pipe, and the other had all of the sound associated with it. I have no idea what to begin to work on for this thing to start driving again. Any help would be appreciated..