After about 30 sec, chugs, loses power, Check Engine Light on; only 2 cylinders

What is your question?

Still trying to get my 1992 Ford Explorer 4.0L 4dr Auto 4WD VIN X to run properly. Here's the current situation: It starts fine, runs about 30 seconds, then chugs, loses power, and Check Engine Light comes on. What we've discovered: It is running on only 2 cylinders now. When I pull the the wires off the coil, here's what I find: Cylinders 1 and 5 do not spark at all. Cylinders 2 and 6 spark but do not fire. Cylinders 3 and 4 spark and fire. When I first got this Explorer, the engine ran fine. These problems occurred after it failed a smog test. (It probably would not have failed had anyone noticed that a 1' piece of tailpipe was missing between the catalytic converter and the exhaust pipe, which I've since installed). After making many attempts, codes were pulled but were random so I replaced O2 sensor, crankshaft position sensor, MAF, cleaned the Idle adjust sensor, replaced vacuum tubes, repaired a few broken ground wires, re-installed the 'retard timing' octane jumper. I base the cylinder numbers on this diagram: 3 4 -- sparking and firing 2 6 -- sparking, not firing 1 5 -- no sparking, no firing (Coil looking from the front) Cylinders on the engine are numbered 3 6 2 5 1 4